JP2006113529A - Intermediate transfer member and image forming apparatus using the intermediate transfer member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate transfer member which can suppress flying-off of toner in a state where a volume resistivity of the intermediate transfer member is high when primary transfer and second transfer are performed with a transfer electric field, and from which charges generated by the transfer electric field can easily be eliminated; and to provide an image forming apparatus which ensures few image defects due to flying-off of toner (blur) and can stably give high transferred image quality. <P>SOLUTION: The intermediate transfer member comprises at least a substrate and a surface layer disposed on the substrate, wherein the surface layer is a photoconductive layer containing a fullerene. The image forming apparatus is equipped with the intermediate transfer member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an intermediate transfer member used in an image forming apparatus using an electrophotographic system such as a copying machine or a printer, and an image forming apparatus using the intermediate transfer member.

In an image forming apparatus using an electrophotographic method, first, a uniform charge is formed on the surface of an image carrier made of a photoconductive photoreceptor made of an inorganic or organic material, and the image signal is modulated with a laser beam or the like. After the electric image is formed, the electrostatic image is developed with a charged toner to form a visualized toner image. The toner image is electrostatically transferred to a recording material such as recording paper via an intermediate transfer member or directly, and the transferred toner image is fixed on the recording material to obtain a required reproduced image. It is done.
In particular, there is known an image forming apparatus that employs a system in which a toner image formed on the image carrier is primarily transferred to an intermediate transfer member, and further, a toner image on the intermediate transfer member is secondarily transferred to a recording material ( For example, see Patent Document 1.)

In the image forming apparatus employing the intermediate transfer body method, as a material used for the intermediate transfer body, a material in which a filler such as carbon or a metal compound is dispersed as a conductive agent in a polymer material is used. Polycarbonate resin, PVDF (polyvinylidene fluoride), polyalkylene phthalate, blend material of PC (polycarbonate) / PAT (polyalkylene terephthalate), ETFE (ethylene tetrafluoroethylene copolymer) / PC, ETFE / PAT, PC / PAT A proposal has been made to use a conductive endless belt made of a thermoplastic resin, which is a blend material (see, for example, Patent Documents 2 to 7). In addition, an intermediate transfer belt in which a conductive filler is dispersed in a polyimide resin excellent in mechanical properties and heat resistance has been proposed (see, for example, Patent Documents 8 and 9).
It is known that there is a close relationship as shown below between the volume resistivity of such an intermediate transfer member and the image quality of the toner image.

(When the volume resistivity ρv of the intermediate transfer member is low)
It is known that when the volume resistivity ρv of the intermediate transfer member is too low (ρv ≦ 10 ⁸ Ωcm), toner splatters during transfer and the image quality deteriorates (see, for example, Patent Document 10). . When the volume resistivity of the intermediate transfer member is too low, the transfer electric field and the transfer current due to the primary transfer roll cause the transfer electric field to be easily applied to the area without the toner layer, thereby expanding the transfer area. This is thought to be due to splattering and being transferred.

(When the volume resistivity of the intermediate transfer member is intermediate)
As an intermediate transfer member of an image forming apparatus that is currently in practical use, one having an intermediate volume resistivity (10 ⁸ Ωcm ≦ ρv ≦ 10 ¹⁴ Ωcm) is used. In such an image forming apparatus, the charged charge is appropriately attenuated by the semiconductivity of the intermediate transfer member. In other words, the average value of the volume resistivity of the intermediate transfer member is in a range where the charged charges are appropriately attenuated (volume resistivity is in an appropriate range), so that image formation is continuously performed without using a neutralizing member. Can do.

However, even if the average value of the volume resistivity of the intermediate transfer member is in the appropriate range (the range in which the charged charge is appropriately attenuated), in such an intermediate transfer member, the primary transfer roll described above is used. Due to the action of the transfer electric field and the transfer current, the transfer electric field is easily applied to the area without the toner layer, so that the transfer area widens, and the problem may occur that the toner is scattered and transferred by the action. In addition, in order to obtain a high-quality transfer image quality in recent years, the toner tends to use a small-diameter spherical toner. If the toner is reduced in diameter or sphere, the toner is easily moved by the transfer electric field, and the toner tends to be more likely to be scattered. Furthermore, the above intermediate transfer member has the following problems.
That is, when a filler such as carbon or a metal compound is dispersed in a polymer resin, the resistance variation in the intermediate transfer body due to the dispersed state of the filler is increased to about one digit or more, and a slight amount between the filler and the filler is small. That is, the resistance of the intermediate transfer member is lowered with time due to dielectric breakdown of the polymer resin portion or filler rearrangement due to energization. As described above, when printing is repeated, there is a problem that the partial or overall volume resistivity of the intermediate transfer member deviates from a suitable width with time, and image quality is deteriorated.

(When the volume resistivity ρv of the intermediate transfer member is high)
When the volume resistivity ρv of the intermediate transfer member is high (ρv> 10 ¹⁴ Ωcm), the charge retention property of the intermediate transfer member in the toner image region increases, and an electric field necessary for transfer can be appropriately applied to the toner. it can. On the other hand, since the charge transfer on the surface of the intermediate transfer member in the adjacent non-image portion and the inside thereof is reduced, toner transfer to this region hardly occurs in the primary and secondary transfer. As a result, when the volume resistivity of the intermediate transfer member is high, a toner-formed image with good image quality can be obtained with less toner scattering.
However, in this case, a process for removing the charge accumulated on the intermediate transfer member after toner transfer is required, and it is difficult to uniformly remove the intermediate transfer member in the charge removal step. The reason why it has not been put into practical use is as follows.

In the case of providing the static elimination step, it is easily assumed that a corotron or a static elimination roll is used as the static elimination member. When neutralizing the intermediate transfer member using a neutralizing roll as the neutralizing member, it is conceivable to use a neutralizing roll to which an AC bias voltage is applied.
In this case, since the surface of the intermediate transfer member and the surface of the charge removal roll have irregularities, it is impossible to bring the entire surface of the intermediate transfer member that rotates into contact with the grounded charge removal roller. For this reason, in an intermediate transfer member having a high volume resistivity, the intermediate transfer member portion that does not contact the charge-removing roll is not easily discharged. That is, when the volume resistivity of the intermediate transfer member is high, there is a problem that it is difficult to reliably discharge the entire surface of the intermediate transfer member in a short time during which the intermediate transfer member passes through the charge removal member. When the unevenness of charge removal occurs on the surface of the intermediate transfer member, there is a problem that the unevenness of density corresponding to the unevenness of charge removal occurs in the toner image primarily transferred to the surface of the intermediate transfer member during the next image formation.
There is also a problem that an expensive high-voltage power supply for static elimination is required because of the static elimination process by discharge.
Further, in the static elimination using the corotron, a large amount of ozone is generated, an image quality defect is generated due to the static elimination unevenness due to the adhesion of the adhering matter to the corotron, an intermediate between discharge products such as NOx, O ₃ and other ozone reaction products. There are problems such as adhesion to the transfer body.

As described above, in the case of using an intermediate transfer body having a high resistivity that exceeds 10 ¹⁴ Ωcm, a neutralizing member that performs neutralization after the completion of the secondary transfer is required. In particular, the value of the volume resistivity ρv The higher the value, the more difficult it is to uniformly remove the entire surface of the intermediate transfer member even if the charge eliminating member is used.
Accordingly, considering only the transfer action, it is advantageous that the intermediate transfer member has a higher volume resistivity. However, the intermediate transfer member having a high resistivity requires a discharging step and it is difficult to remove the charge uniformly. Therefore, conventionally, an image forming apparatus using an intermediate transfer body having a high resistivity with a volume resistivity ρv of ρv> 10 ¹⁴ Ω has not been put into practical use.

Further, the following techniques (1) to (3) are known as those using an intermediate transfer body whose volume resistivity decreases when a physical stimulus is applied in a conventional image forming apparatus (for example, Patent Document 11). ~ 13). Furthermore, the following technique (4) (see, for example, Patent Document 14) is a transfer using a normal transfer electric field, and it is a matter of course that conventional drawbacks cannot be avoided.

In (1) to (3), the reason for using an intermediate transfer body having a reduced resistance value is that in (1), the intermediate transfer body that has been primarily transferred by a special method is neutralized before secondary transfer. This is because in (2) and (3), secondary transfer is performed by utilizing the decrease in the resistance value of the intermediate transfer member. That is, each of (1) to (3) is an image forming apparatus using an intermediate transfer body whose resistance value is lowered to perform special transfer, and an image forming apparatus that performs transfer by a normal transfer electric field. Is a completely different technology. In addition, all of (1) to (4) are idea technologies and are not put into practical use. Moreover, there are problems as described below.

(1) Technology described in Patent Document 11 Here, FIGS. 8 and 9 are explanatory diagrams of the technology described in Japanese Patent Laid-Open No. 7-146616, which is Patent Document 11. FIG. In FIG. 8, Q1 represents a primary transfer region, Q2 represents a secondary transfer region, and 01a and 01b (see FIG. 8B) are blankets (intermediate transfer members) 01 (see FIG. 8A), respectively. The conductive rubber layer 01a mixed with carbon and the silicon rubber layer 01b mixed with a charge generating agent are shown. In FIG. 8C, a blanket 01 having photoconductivity is used as an intermediate transfer member, and the surface of the blanket 01 is charged to a polarity (+) opposite to the charging polarity (−) of the toner. In FIG. 8D, the toner is primarily transferred from the photosensitive drum 02 to the blanket (intermediate transfer member) 01 by the electrostatic force due to the charged charges. In FIG. 8E, after the primary transfer and before the secondary transfer, the light L is applied to the blanket (intermediate transfer member) 01 and the primary transfer toner image on the surface thereof to neutralize the charge (see FIG. 9A). . In FIG. 8F, since the bonding force between the surface of the blanket 01 and the toner is weakened by static elimination, secondary transfer can be easily performed by light irradiation.
However, in this method, as shown in FIG. 9B, the surface of the blanket (intermediate transfer member) 01 is placed on the surface of the photosensitive member as a stage before the primary transfer from the photosensitive drum 02 to the blanket (intermediate transfer member) 01. Since the toner is charged to a polarity opposite to the toner charging polarity on the drum 02, toner transfer occurs in the pre-primary transfer region, and image quality deterioration due to image disturbance or blurring cannot be prevented.

Next, problems that occur when applied to an apparatus that multiplex-transfers a color image using a plurality of colors of toner will be described. In FIG. 9C, after the primary transfer of the first color toner to the blanket (intermediate transfer body) 01, the first color toner on the blanket 01 is prepared for the primary transfer of the second color toner. The toner is charged to a polarity opposite to the toner charging polarity on the drum 02, and the toner on the photosensitive drum 02 is transferred to the blanket 01. At this time, since a transfer electric field sufficient to transfer the toner on the photosensitive drum 02 is applied between the photosensitive drum 02 and the blanket 01, the second color toner on the photosensitive drum 02 is transferred to the blanket 01. To do. In contrast, the first color toner on the blanket 01 having the opposite polarity is transferred to the photosensitive drum 02 (see FIG. 9D).
Therefore, when the intermediate transfer member (blanket 01) described in (1) is applied to an apparatus for multiple transfer of color images, it is very difficult to obtain a color image with good image quality using multiple transfer. .

(2) Technology described in Patent Literature 12 Here, FIG. 10 is an explanatory diagram of the technology described in Japanese Patent Laid-Open No. 5-257398 which is Patent Literature 12. In this publication, as shown in FIGS. 10 (A) and 10 (B), the purpose is to prevent transfer in the pre-transfer area, and as shown in FIG. 10 (C), before the primary transfer. A pre-charge having the same polarity as the toner charging polarity is added to the surface of the photoconductive blanket (intermediate transfer member) 01 by the pre-transfer charger 03, and as shown in FIG. 10D, in the primary transfer region Q1. A method of performing primary transfer by irradiating light from the back of a blanket (intermediate transfer member) 01 has been proposed.
Although this method can reduce the transfer in the pre-transfer area, only a single color image can be obtained, and it is difficult to obtain a clear full-color image.

FIG. 11 is an explanatory diagram of problems that occur when the developed image of the second color is transferred by the technique described in Japanese Patent Laid-Open No. 5-257398 which is Patent Document 12. In FIG. 11, a pre-charge is given to the first color toner image already transferred onto the blanket (intermediate transfer member) 01 (see FIG. 11A), and light is irradiated from the back surface in the primary transfer region Q1. Transfer is performed (see FIG. 11B). At this time, the charge of the blanket (intermediate transfer member) 01 is discharged, but the toner charge of the first color is not discharged.
As a result, there is a problem that the toner of the second color is scattered and uneven due to the electric field due to the toner charge that is not neutralized for the first color.

(3) Technology described in Patent Document 13 Here, FIG. 12 shows the transfer by light irradiation using an intermediate transfer body whose resistance value is reduced by light irradiation described in JP-A-6-282181, which is Patent Document 13. It is explanatory drawing of the technique to perform. FIG. 13 is an explanatory diagram of a technique for performing transfer by applying pressure using an intermediate transfer body whose resistance value is reduced by pressure, as described in JP-A-6-282181.
In FIG. 12, a transfer material 04 such as paper is electrostatically held on a blanket (intermediate transfer member) 01, irradiated with light from the back surface of the blanket (intermediate transfer member) 01 in a transfer region Q1, and charged by a charge generation layer 01c. There has been proposed a method of transferring a toner image on the photosensitive drum 02 by applying a transfer electric field due to the generated holes. In this method, since the transfer electric field is applied by reducing the resistance of the intermediate transfer body 01 by the action of light or the like in the transfer region Q1, the axial direction of the photosensitive drum 02 (perpendicular to the paper traveling direction). It has a low resistance. For this reason, there is a problem that it is difficult to prevent scattering and blurring of the toner image in the axial direction.
FIG. 13 is a technique for performing transfer by reducing resistance by applying pressure by a roll instead of the light irradiation of FIG. 12, but the technique shown in FIG. 13 has the same problems as the technique shown in FIG. . Further, it is difficult to apply a uniform pressure to the intermediate transfer member due to the bending of the shaft of the intermediate transfer member support roll, surface irregularities, and the like, and there is a problem that transfer unevenness due to pressure distribution unevenness occurs.

(4) Technology described in Patent Literature 14 The technology described in Patent Literature 14 uses carbon black and a semiconductive polymer belt containing fullerene as a conductivity imparting agent as a transfer belt. As described in this document, the intermediate transfer member is composed only of a base material, and the base material contains fullerene. By containing fullerene, the variation width of resistance becomes small, stable and good transferability can be obtained, and the effect of improving transfer efficiency is recognized. However, further improvements have been desired for toner scattering.

As described above, the conventional intermediate transfer member has various problems, and a technique capable of solving these problems is desired.
JP-A-62-206567 JP-A-6-095521 Japanese Patent Laid-Open No. 5-200904 JP-A-6-228335 Japanese Patent Laid-Open No. 6-149081 Japanese Patent Laid-Open No. 6-149083 Japanese Patent Laid-Open No. 6-149079 JP-A-5-77252 Japanese Patent Laid-Open No. 10-63115 Japanese Unexamined Patent Publication No. Hei 8-248879 JP-A-7-146616 JP-A-5-257398 JP-A-6-282181 JP 2002-14543 A

  As described above, in the conventional intermediate transfer type image forming apparatus, toner scattering due to the charging characteristics of the intermediate transfer member is likely to occur, and it may be difficult to stably obtain a high-quality image. In addition to this, as the toner used has a smaller diameter and a substantially spherical shape, there is a tendency that poor cleaning of the surface of the intermediate transfer member, which causes a reduction in image quality, is likely to occur.

  An object of the present invention is to solve the above problems. That is, the present invention suppresses the occurrence of toner scattering, and is excellent in the cleaning property of the toner remaining on the surface of the intermediate transfer member after the secondary transfer, even if a toner having a smaller diameter and a substantially spherical shape is used. An object of the present invention is to provide an image forming apparatus capable of stably forming the image.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> An intermediate transfer body having at least a base material and a surface layer provided on the base material,
The intermediate transfer member, wherein the surface layer is a photoconductive layer containing fullerene.

<2> The photoconductive layer has at least a charge generation layer and a charge transport layer,
The charge generation layer is provided between the base material and the charge transport layer,
The intermediate transfer member according to <1>, wherein the charge transport layer contains fullerene.

<3> The intermediate transfer member according to <1> or <2>, wherein the layer farthest from the base material among the surface layers contains a fluorine-based resin.

<4> The intermediate transfer member according to any one of <1> to <3>, wherein the substrate has a volume resistivity of 1 × 10 ⁶ to 1 × 10 ¹³ Ωcm.

<5> The intermediate transfer member according to any one of <1> to <4>, wherein the base material includes a polyimide resin containing a conductive agent.

<6> An intermediate layer is provided between the base material and the surface layer,
The intermediate transfer according to any one of <1> to <5>, wherein the intermediate layer has a JIS A hardness in a range of 40 to 70 degrees, and a Young's modulus of the resin material is 2000 MPa or more. Is the body.

<7> An image carrier on which a toner image is formed using a developer containing toner;
An outer peripheral surface abuts on the surface of the image carrier, a primary transfer portion that transfers the toner image from the surface of the image carrier to the outer peripheral surface, and the toner image transferred to the outer peripheral surface to a transfer material. An intermediate transfer member composed of a rotating member having a secondary transfer portion to be transferred;
Light neutralizing means for eliminating static electricity by irradiating the outer peripheral surface of the intermediate transfer body after passing through the secondary transfer portion with light, and the intermediate transfer body is any one of <1> to <6> An image forming apparatus comprising the intermediate transfer member according to item 1.

<8> Furthermore, a cleaning means for cleaning the outer peripheral surface of the intermediate transfer member after the charge removal is provided,
The cleaning means includes one or more cleaning units including a brush member that contacts the outer peripheral surface of the intermediate transfer member, and a voltage is applied to the brush member when cleaning the outer peripheral surface of the intermediate transfer member. The image forming apparatus according to <7>, wherein:

<9> The cleaning unit according to <8>, wherein the cleaning unit includes the brush member, a conductive roll in contact with the brush member, and a blade disposed in contact with the conductive roll. This is an image forming apparatus.

<10> One or more cleaning units are arranged in series along the rotation direction of the intermediate transfer member,
The polarity of the voltage applied to the brush member of the cleaning unit arranged on the most upstream side in the rotational direction of the intermediate transfer member and the polarity of the toner constituting the toner image held on the surface of the image carrier The image forming apparatus according to <8> or <9>, wherein the image forming apparatuses are different.

<11> Two or more cleaning units are arranged in series along the rotation direction of the intermediate transfer member,
Any one of the above <8> to <10>, wherein polarities of voltages applied to brush members of one cleaning unit and another cleaning unit disposed adjacent thereto are different from each other. The image forming apparatus described.

<12> Furthermore, a cleaning means for cleaning the outer peripheral surface of the intermediate transfer member after the static elimination is provided,
The image forming apparatus according to <7>, wherein the cleaning unit includes a cleaning blade that contacts an outer peripheral surface of the intermediate transfer member.

<13> The cleaning blade is formed of urethane rubber,
[1] The rebound resilience coefficient defined by [1] JIS K6255 of the urethane rubber is 20% or more at 10 ° C. and 70% or less at 40 ° C., and [2] 300% modulus defined by JIS K6251 is 2000 N / cm ² or more, the tear strength of the angle type is defined by and [3] JIS K6252, an image forming apparatus according to <12>, wherein the at 700 N / cm or more.

<14> The image forming apparatus according to <13>, wherein the cleaning blade has a 100% permanent elongation defined by JIS K6262 of 2.5% or less.

<15> A cleaning brush in which the cleaning unit is in contact with the outer peripheral surface of the intermediate transfer member and is rotatable, and a lubricant application unit that applies a solid lubricant to the outer peripheral surface of the intermediate transfer member through the cleaning brush. Including
The image forming apparatus according to <12>, wherein the cleaning brush is disposed upstream of the cleaning blade in the rotation direction of the intermediate transfer member.

<16> The linear pressure on the outer peripheral surface of the intermediate transfer member of the cleaning blade is in the range of 0.2 to 0.5 N / cm, and the contact angle is in the range of 22 to 32 degrees.
The blade material constituting the cleaning blade has a rebound coefficient of elasticity defined by JIS K6255 within a range of 45 to 65% at 40 ° C. and a 300% modulus defined by JIS K6251 of 1000 to 2500 N / cm ² . The image forming apparatus according to <15>, wherein the image forming apparatus is within a range.

<17> The image according to any one of <7> to <16>, wherein a shape factor SF defined by the following formula (1) of the toner is in a range of 100 to 140. Forming device.

Formula (1); SF = [(maximum length of toner particles) ² × π × 100] / [projection area of toner particles × 4]

In the prior art (4) (Japanese Patent Laid-Open No. 2002-14543), the intermediate transfer member contains fullerene, but it is not planned to irradiate the intermediate transfer member with light. The base material contains fullerene. However, the present invention aims to change the volume resistivity by irradiating the intermediate transfer member with light, so that the layer structure has a surface layer (photoconductive layer) in addition to the substrate. It differs from the configuration of technology (4).
Further, it has been unknown in the prior art (4) how the physical property value of the surface layer changes when the surface layer containing fullerene is irradiated with light. However, the present inventors have found that a layer containing fullerene is suitable as an intermediate transfer member in terms of the rate of change in volume resistivity and the rate of change, leading to the above invention.

On the other hand, in the prior arts (1) to (3), a charge generating agent is added to the intermediate transfer member and light irradiation is performed, but the structure of the charge transport layer for transporting the generated charges is conventional. The charge transport property of the charge transport layer is not changed by light irradiation.
In the intermediate transfer member of the present invention, the charge generation material generates charges when irradiated with light, and the conductivity of the layer is changed by fullerene, so that the charge transport property is enhanced. That is, the intermediate transfer member can efficiently transport the generated charges.

  In the prior art (1) (Japanese Patent Laid-Open No. 7-146616), light is irradiated in the process between the primary transfer and the secondary transfer, and the conventional techniques (2) and (3) (Japanese Patent Laid-Open No. 5). -257398 and 6-282181) irradiate light during transfer. All of these are methods for increasing the transfer efficiency to the transfer target, and do not irradiate light to clean the intermediate transfer member. In addition, although these transfer techniques have improved transfer efficiency, the toner remaining on the intermediate body without being transferred is charged, causing transfer in a pre-transfer area or multiple transfer for obtaining a color image. It was difficult.

The present inventors have also found that it is preferable to use the fullerene-containing intermediate transfer member of the present invention when light irradiation is used as a method for neutralizing the intermediate transfer member. Based on this knowledge, an image forming apparatus provided with a neutralizing device by light irradiation to the intermediate transfer member after the secondary transfer and having an intermediate transfer member containing fullerene is also presented.
Furthermore, it has been found that the image forming apparatus of the present invention has good cleaning properties when the above-described cleaning device is used. Accordingly, an image forming apparatus including such a cleaning device is provided.

  According to the present invention, when primary transfer and secondary transfer are performed using a transfer electric field, toner scattering can be suppressed in a state where the volume resistivity of the intermediate transfer member is high, and the transfer electric field is generated. It is possible to provide an intermediate transfer member that can easily remove the charge of the intermediate transfer member.

  Further, by providing such an intermediate transfer member and a charge eliminating means for discharging the charge of the intermediate transfer member, image quality defects due to toner scattering (blur) are remarkably reduced, and high-quality transfer image quality can be stably obtained. It is possible to provide an image forming apparatus capable of performing the above.

  Further, by providing the cleaning means according to the present invention, the occurrence of toner scattering is suppressed, and even when toner having a smaller diameter and a substantially spherical shape is used, the toner remaining on the surface of the intermediate transfer member after the secondary transfer is reduced. It is possible to provide an image forming apparatus that is excellent in cleaning property and can stably form a high-quality image.

  Hereinafter, the intermediate transfer member and the image forming apparatus of the present invention will be described in detail.

<Intermediate transfer member>
The intermediate transfer body of the present invention is an intermediate transfer body having a base material and a surface layer provided on the base material, and the surface layer is a dielectric in a state where light is not irradiated and has a volume resistance. The photoconductive layer has a high rate and exhibits conductivity when irradiated with light, and the photoconductive layer contains fullerene. By providing such a photoconductive layer, it is possible to suppress the scattering of toner in a state where the volume resistivity of the intermediate transfer member is high, and the charge of the intermediate transfer member can be eliminated by light irradiation. Can be easily performed.
In the present invention, the surface layer is a dielectric layer in a state where light is not irradiated and has a high volume resistivity, and in the state where light is irradiated, either a negative electron or a positive hole is used. A photoconductive layer having a charge transport layer that transports charges by carriers of the above, and a charge generation layer that is provided between the charge transport layer and the base material and generates a charge when irradiated with light, The charge transport layer preferably contains fullerene.
In addition, when a fluorine-based resin is contained in the outermost surface layer among the surface layers, an intermediate transfer member excellent in durability against toner contamination is obtained.
The intermediate transfer member of the present invention can be configured in a drum shape or a belt shape.
Hereinafter, each member constituting the intermediate transfer member of the present invention will be described.

[Surface layer]
In the intermediate transfer member of the present invention, the surface layer is a dielectric material that has a high volume resistivity when not irradiated with light, and is electrically conductive when irradiated with light, and contains fullerene. It is characterized by doing. The photoconductive layer may have a structure in which fullerene is added to the material constituting the surface layer of the intermediate transfer body, or the layer structure used for the electrophotographic photoreceptor can be diverted. In this case, the photoconductive layer may have a multilayer structure including a charge transport layer and a charge generation layer, or may have a single layer structure, but the former multilayer photoconductive layer is preferred.

Thus, since the surface layer is a photoconductive layer, it has a volume resistivity of a dielectric when not irradiated with light and exhibits conductivity when irradiated with light, and the volume resistivity is reduced by light irradiation. It is a layer.
In such an intermediate transfer member, the primary transfer and the secondary transfer are performed without light irradiation. At this time, the intermediate transfer member has a high volume resistivity equivalent to that of a dielectric. For this reason, when an intermediate transfer body having such a high volume resistivity is used and a transfer voltage is applied, the transfer electric field does not spread and toner scattering can be suppressed, and a good transfer image can be obtained. it can.

In the intermediate transfer body of the present invention, the surface layer which is a photoconductive layer is a dielectric body in a state where light is not irradiated, so that the volume resistivity of the intermediate transfer body is as high as 1 × 10 ^13.5 Ωcm or more. Preferably 1 × 10 ¹⁴ Ωcm or more.
Further, when the light is irradiated, the charge generation layer generates charges, so that the resistivity of the intermediate transfer member is changed to show conductivity. In addition, in the present invention, since the charge transport layer contains fullerene as shown below, the resistivity of the charge transport layer also changes and further shows conductivity. The volume resistivity of the surface layer at the time of irradiation is preferably 1 × 10 ¹⁰ Ωcm or more and 1 × 10 ¹² Ωcm or less, and more preferably 1 × 10 ^10.4 Ωcm or more and 1 × 10 ^11.6 Ωcm or less.

Here, the volume resistivity of the intermediate transfer member of the present invention can be measured according to JIS K 6911 (1995 version) using a circular electrode (for example, HR probe of Hiresta IP manufactured by Dia Instruments). . A method for measuring the volume resistivity will be described with reference to the drawings.
FIG. 6 is a schematic plan view (A) and a schematic cross-sectional view (B) showing an example of a circular electrode. The circular electrode shown in FIG. 6 includes a first voltage application electrode A ′ and a second voltage application electrode B ′. The first voltage application electrode A ′ has a cylindrical electrode part C ′ and a cylindrical shape having an inner diameter larger than the outer diameter of the cylindrical electrode part C ′ and surrounding the cylindrical electrode part C ′ at a constant interval. Ring-shaped electrode portion D ′. The intermediate transfer belt 22 is sandwiched between the second voltage application electrode B ′ and the cylindrical electrode part C ′ and the ring electrode part D ′ in the first voltage application electrode A ′, and the circle in the first voltage application electrode A ′. The current I (A) that flows when the voltage V (V) is applied between the columnar electrode portion C ′ and the second voltage application electrode B ′ is measured, and the volume of the intermediate transfer body 1 is calculated by the following equation (2). The resistivity ρv (Ωcm) can be calculated. Here, in the following formula (2), t represents the thickness of the intermediate transfer member 1.
Formula (2); ρv = 19.6 × (V / I) × t

  Further, the surface resistivity ρs (Ω / □) of the intermediate transfer member is determined between the cylindrical electrode portion C ′ and the ring electrode portion D ′ of the first voltage application electrode A ′ using the circular electrode of FIG. The current I (A) that flows when the voltage V (V) is applied can be measured and calculated by the following equation (3).

    Formula (3); ρs = 19.6 × (V / I)

  The volume resistivity and surface resistivity of the surface layer can be measured using the above intermediate transfer member.

  In order to design the photoconductive layer so as to have such a volume resistivity, in the present invention, the photoconductive layer contains fullerene. Since fullerene has good reactivity with light, it is very suitable for use in an intermediate transfer member from the rate of change in conductivity and the rate of change. As described above, when the photoconductive layer has a charge generation layer and a charge transport layer, when the fullerene is contained in the charge transport layer, the charge generated in the charge generation layer is efficiently transported. Can do. Therefore, in an image forming method and apparatus using an intermediate transfer member that employs light irradiation as a charge eliminating method, transfer efficiency is good and toner scattering is extremely reduced.

  An intermediate transfer member (for example, JP-A-7-146616, JP-A-5-257398, etc.) used in an image forming method having conventional light irradiation in a process contains a charge generator, but is electrically conductive by light. Since no charge transporting layer is provided, the reactivity with respect to light is lower than that of the intermediate transfer member of the present invention. On the other hand, even an intermediate transfer member containing fullerene has not been supposed to be irradiated with light conventionally (for example, Japanese Patent Application Laid-Open No. 2002-14543). Therefore, variation in resistance due to fullerene is suppressed and density unevenness is reduced. Although it is possible, it has been difficult to carry out static elimination efficiently. As described above, the conventional intermediate transfer member has a completely different structure and mechanism that does not use the photoconductivity of fullerene and does not use a charge generating agent.

  Therefore, it was completely unpredictable whether these combinations of charge generating agent and fullerene were efficient and effective for light irradiation. Although the mechanism of the present invention has not been clarified, the relationship between the rate of charge generation by the charge generating agent and the rate of change of conductivity by fullerene from the reactivity to light and the value of volume resistivity at the time of light irradiation, Various factors such as the relationship between the charge generation efficiency of the charge generating agent and the fullerene are considered to be suitable for the conditions for use as an intermediate transfer member.

Fullerene particles have an electrical resistivity of about 1 × 10 ¹² Ωcm or less. Molecular fullerenes are described as hollow, fully spheroid shells of carbon atoms that contain 32 to 1,000 or more carbon atoms in each sphere. For this, see Smalley, RE, “Supersonic Carbon Cluster Beams in Atomic and Molecular Clusters,” Bernstein, ER and Physical and Theoretical. Reference may be made to Chemistry (Physical and Theoretical Chemistry), Vol. 68, Elsevier Science: NY, 1990, pp. 1-68, the entire disclosure of which is incorporated herein by reference.

The original fullerene, C _60, is called Buckminsterfullerene, is a truncated icosahedron molecular geometry, similar to a molecular size soccer ball. C ₆₀ , C ₇₀ and other fullerene molecules are also called buckyballs. Buckminsterfullerenes, usually by C ₇₆ and C ₈₄ molecules with a small amount of C ₇₀ and optionally, or constituted by contaminated C ₆₀ molecules with a small amount of C _50. Still other fullerenes include C ₈₂ , C ₈₈ and C ₉₀ molecules.
In addition to the shape of the buckyball or the like, the fullerene has an annular shape or a helix structure as described in, for example, Business Week, 1991 (December 9), pp. 76-77. be able to.

  Preparation of buckminsterfullerenes and other fullerenes by contact arc vaporization of graphite and the properties of a number of buckminsterfullerenes, such as solubility, crystallinity, color, etc. are found in Kratsschmer, W. Lamb, LD, Fostiropoulos, K.M. Huffman, D.R., Nature, 1990, 347, pp. 354-358, and Chemical and Engineering News, 1990 (October 29), pp. 22-25. The entire disclosure of these documents is the reference of the present invention.

Fullerenes can be controlled in various light absorption wavelengths and molar extinction coefficients by chemical modification, and are preferably selected according to the spectrum of irradiated light. Moreover, the effect is almost equal even if it uses a mixture without considering a high-purity product from a price consideration.
In the present invention, fullerenes of any molecular weight can be applied, but C ₆₀ , C ₇₀ , and C ₇₆ are preferable from the viewpoint of improving static elimination efficiency and resistance variation, and availability. More preferably, it is _C60 .

  Fullerene is currently manufactured and sold by Frontier Carbon Co., Ltd. (Headquarters: Tokyo, Japan), and the high-purity products and mixtures of fullerenes listed in the catalog are included in this patent. Various fullerenes can be used alone or in combination of two or more.

  The amount of fullerene to be contained in the photoconductive layer is not particularly limited as long as it is within a range satisfying the volume resistivity. The preferred fullerene content varies depending on the type of fullerene to be used (difference in purity and molecular weight), but as an example, it is preferably 1% by mass to 30% by mass, more preferably 3% by mass to 20% by mass. It is.

In particular, in the present invention, the photoconductive layer preferably has a multilayer structure having a charge transport layer and a charge generation layer. The charge generation layer is provided between the charge transport layer and the substrate.
The charge transport layer is a dielectric layer and has a high volume resistivity when not irradiated with light. In addition, the charge generation layer does not generate charges in a state where light is not irradiated.
On the other hand, when light is irradiated, charges are generated in the charge generation layer. The generated charges are transported in the charge transport layer by carriers of either negative polarity electrons or positive polarity holes. Since the charge transport layer contains fullerene, the conductivity of the charge transport layer is also increased during light irradiation.
That is, in the case of a photoconductive layer having a charge transport layer and a charge generation layer, if the charge transport layer contains fullerene, the charge generated by light irradiation can be efficiently transported.

Hereinafter, the photoconductive layer having the charge transport layer and the charge generation layer will be described in detail.
Such a multi-layered photoconductive layer may be any other layer, for example, an undercoat layer or a surface protective layer, as long as the charge generation layer is provided between the charge transport layer and the substrate. May be included.

First, using FIG. 5, each layer constituting this multilayer structure will be described in order.
Here, FIG. 5A is a schematic sectional view showing an example of the configuration of the intermediate transfer member 100a of the present invention, and FIG. 5B is a schematic sectional view showing another example of the configuration of the intermediate transfer member 100b of the present invention. FIG. (C) is a schematic sectional view showing another example of the configuration of the intermediate transfer member 100c of the present invention, and (D) is a schematic sectional view showing another example of the configuration of the intermediate transfer member 100d of the present invention.
As shown in FIG. 5A, an example of the configuration of the intermediate transfer member 100a of the present invention includes a base 110 and a photoconductive layer 120. The photoconductive layer 120 is an undercoat layer 122. And a charge generation layer 124 and a charge transport layer 126.
Further, as shown in FIG. 5B, another example of the configuration of the intermediate transfer member in the present invention includes a base 110 and a photoconductive layer 120. The pulling layer 122, the charge generation layer 124, the charge transport layer 126, and the surface protective layer 128 are included.
As shown in FIG. 5C, another example of the configuration of the intermediate transfer member of the present invention includes a base 110, an elastic layer 115, and a photoconductive layer 120. The photoconductive layer 120 includes: The undercoat layer 122, the charge generation layer 124, the charge transport layer 126, and the surface protective layer 128.
Furthermore, as shown in FIG. 5D, another example of the configuration of the intermediate transfer member of the present invention includes a base 110, an adhesive layer 113, an elastic layer 115, and a photoconductive layer 120. The photoconductive layer 120 includes an undercoat layer 122, a charge generation layer 124, a charge transport layer 126, and a surface protective layer 128.

[Charge generation layer]
The charge generation layer is a layer provided between the base material and the charge transport layer and has a function of generating charges in a state where light is irradiated. Such a charge generation layer is formed by forming a charge generation material by vacuum vapor deposition or by dispersing and applying the charge generation material together with an organic solvent and a binder resin.

  The charge generation material used in the charge generation layer includes amorphous selenium, crystalline selenium, selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and selenium alloys, zinc oxide, titanium oxide, and other inorganic photoconductive materials. And sensitized dyes; metal-free phthalocyanine, titanyl phthalocyanine, copper phthalocyanine, tin phthalocyanine, gallium phthalocyanine and other phthalocyanine pigments, squalium, anthanthrone, perylene, azo, anthraquinone, pyrene , Various organic pigments and dyes such as pyrylium salt and thiapyrylium salt are used. In addition, these organic pigments generally have several types of crystals. In particular, phthalocyanine pigments are known for various crystal types including α-type and β-type. Any of these crystal forms can be used as long as it is a pigment capable of obtaining the above characteristics.

In the present invention, the following compounds are particularly suitable as a charge generating material that can provide excellent performance. That is, at the Bragg angles (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα rays, diffraction peaks are at least at positions of 7.6 °, 10.0 °, 25.2 °, 28.0 °. At least 7.3 °, 16.5 °, 25.4 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using hydroxygallium phthalocyanine typified by a crystal form having Ckα rays , At least 9.5 ° in a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum using a chlorogallium phthalocyanine represented by a crystal type having a diffraction peak at a position of 28.1 ° and a Cukα ray. , 24.2 °, 27.3 °, titanyl phthalocyanine typified by a crystal form having a diffraction peak.
Note that the position of these peak intensities may slightly deviate from the above values depending on the crystal shape and measurement method, but if the X-ray diffraction patterns basically match, it is determined that they are the same crystal type. it can.
These charge generation materials can be used alone or in combination of two or more.

  Examples of the binder resin used in the charge generation layer include the following. Polycarbonate resin such as bisphenol A type or bisphenol Z type and copolymer thereof; polyarylate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer resin, Examples thereof include vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole and the like.

These binder resins can be used alone or in combination of two or more. The blending ratio (mass ratio) between the charge generating substance and the binder resin is preferably in the range of 10: 1 to 1:10.
As a method for dispersing the charge generating material in the binder resin, methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a dyno mill, a sand mill, and a colloid mill can be used.
The thickness of the charge generation layer is generally set in the range of 0.01 to 5 μm, preferably 0.05 to 2.0 μm.

Note that the light absorption in the charge generation layer varies by changing the thickness of the charge generation layer, but the light absorption increases by increasing the thickness of the charge generation layer, and the film thickness in the entire photoconductive layer. Even if there is a distribution, variation in sensitivity to light can be reduced, and in-plane uniformity of transfer efficiency can be improved.
Note that the amount of reflected light of the charge generation layer is influenced not only by the film thickness but also by the absorption coefficient of the pigment with respect to the irradiation light, the blending ratio of the pigment and the binder resin, and the dispersion state of the pigment. It is not specified from the thickness.

[Charge transport layer]
The charge transport layer is a layer provided on the surface of the charge generation layer described above, and is a dielectric layer that has a high volume resistivity when not irradiated with light, and has a negative polarity electron or state when irradiated with light. It has a function of transporting charges by any carrier of positive holes. Such a charge transport layer is formed by dissolving a charge generation material and a binder resin in a suitable solvent and coating them.

Examples of the charge transport material used in the charge transport layer include those shown below. Oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenylpyrazoline, 1- [pyridyl- (2)]-3 -Pyrazoline derivatives such as (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, tri (p-methylphenyl) amine, N, N-bis (3,4-dimethylphenyl) biphenyl- Aromatic tertiary amino compounds such as 4-amine, dibenzylaniline, 9,9-dimethyl-N, N-di (p-tolyl) fluorenon-2-amine, N, N′-diphenyl-N, N ′ Aromatic tertiary diamino compounds such as bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine, 3- (4′dimethylaminopheny ) -5,6-di- (4′-methoxyphenyl) -1,2,4-triazine, 1,2,4-triazine derivatives, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4-diphenylamino Benzaldehyde-1,1-diphenylhydrazone, [p- (diethylamino) phenyl] (1-naphthyl) phenylhydrazone, 1-pyrenediphenylhydrazone, 9-ethyl-3-[(2methyl-1-indolinylimino) methyl] Carbazole,-(2-methyl-1-indolinyliminomethyl) triphenylamine, 9-methyl-3-carbazole diphenylhydrazone, 1,1'-di (4,4'-methoxyphenyl) acrylaldehyde diphenylhydrazone, β , Β-Bis (methoxyphenyl) vinyldiphenylhydrazone Any hydrazone derivative, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, benzofuran derivatives such as 6-hydroxy-2,3-di- (p-methoxyphenyl) -benzofuran, p- (2,2-diphenylvinyl ) Hole transport materials such as α-stilbene derivatives such as —N, N-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly-N-vinylcarbazole and derivatives thereof. Quinone compounds such as chloranil, bromoanil, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2- ( 4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, 2,5 -Oxadiazole compounds such as bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ', 5,5'tetra-t-butyldiphenoquinone, 3 , 5-dimethyl-3 ', 5'-di-t-butyl-4,4'-diphenoquinone compounds such as diphenoquinone, etc., or groups comprising the compounds shown above Like the main chain or a polymer having in the side chain.
These charge transport materials can be used alone or in combination of two or more.

Further, the fullerene is preferably added to the charge transport layer.
The fullerene can function as a charge injecting material as long as the fullerene concentration and the total electric field are sufficient to cause rapid polarization of the fullerene and to inject charge carriers into the transport layer. The fullerene added to the charge transport layer may be any of the above types. Examples of preferable fullerenes include those described in the surface layer.

  The amount of fullerene added to the charge transport layer varies depending on the type of fullerene as in the case of the surface layer, but is preferably 1% by mass to 30% by mass, and 3% by mass to 20% by mass. Is more preferable. Moreover, it is preferable to adjust suitably the addition ratio of the said charge transport material and fullerene so that it may become in the range of the volume resistivity of a suitable surface layer.

  Since the charge polarity of the photoconductive layer varies depending on the charge transport polarity of the charge transport material, the charge polarity of the intermediate transfer member is determined by the charge transport polarity of the charge transport material. When a hole transport material is used, the intermediate transfer member is used with negative charge, and when an electron transport material is used, the intermediate transfer member is used with positive charge. Further, when both are mixed as a charge transport material, the intermediate transfer member has both charged polarities.

Any binder resin can be used for the charge transport layer, and it is particularly desirable that the binder resin is compatible with the charge transport material and has an appropriate strength.
Examples of binder resins include various polycarbonate resins and copolymers thereof such as bisphenol A, bisphenol Z, bisphenol C, and bisphenol TP; polyarylate resins and copolymers thereof; polyester resins, methacrylic resins, acrylic resins, poly Vinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, silicone resin Silicone alkyd resin, phenol-formaldehyde resin, styrene-acrylic copolymer resin, ethylene-alkyd resin, poly-N-vinylcarbazole resin, polyvinyl butyral resin, polyphenylene ether resin, etc. It is.
These binder resins can be used alone or as a mixture of two or more.
The molecular weight of the binder resin used in the present invention is appropriately selected depending on the film forming conditions such as the film thickness of the photoconductive layer and the solvent, but is usually 3000 to 300,000 in terms of viscosity average molecular weight, more preferably 20,000 to A range of 200,000 is appropriate.

The charge transport layer can be formed by applying and drying a solution in which the charge transport material and the binder resin shown above are dissolved in a suitable solvent.
Examples of the solvent used for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene and chlorobenzene; ketones such as acetone and 2-butanone; halogenation such as methylene chloride, chloroform and ethylene chloride. Aliphatic hydrocarbons; cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol, diethyl ether; or a mixed solvent thereof can be used.
A small amount of silicone oil can be added to the coating solution as a leveling agent for improving the smoothness of the coating film.

Coating methods include dip coating, ring coating, spray coating, bead coating, blade coating, roller coating, knife coating, curtain coating, etc., depending on the shape and application of the intermediate transfer member. It can be done using the method. Moreover, it is preferable to dry by heating after drying by touching at room temperature. The heat drying is desirably performed at a temperature in the range of 30 ° C. to 200 ° C. for a time in the range of 5 minutes to 2 hours.
The compounding ratio of the charge transport material and the binder resin is preferably 10: 1 to 1: 5.
The thickness of the charge transport layer is generally 5 to 50 μm, preferably 10 to 40 μm.

Additives such as antioxidants, light stabilizers, heat stabilizers, etc. to the charge transport layer for the purpose of preventing degradation due to ozone, oxidizing gas, or light / heat generated in the electrophotographic apparatus. be able to.
For example, examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds.

Specific examples of antioxidant compounds are shown below.
Examples of phenolic antioxidants include 2,6-di-t-butyl-4-methylphenol, styrenated phenol, and n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxy. Phenyl) -propionate, 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2-t-butyl-6- (3′-tert-butyl-5′-methyl-2′-) Hydroxybenzyl) -4-methylphenyl acrylate, 4,4'-butylidene-bis- (3-methyl-6-tert-butyl-phenol), 4,4'-thio-bis- (3-methyl-6-t -Butylphenol), 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis- [methylene-3- (3 ', 5'-di-t- Butyl-4'-hydroxy -Phenyl) propionate] -methane, 3,9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4 , 8,10-tetraoxaspiro [5,5] undecane, 3-3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) stearyl propionate, and the like.

  Examples of hindered amine compounds include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy]- 2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine succinate Polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl} {(2,2,6,6-tetra Methyl-4-piperidyl) imino} hexamethylene {(2,3,6,6-tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl)- 2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl- N- (1,2,2,6,6, -pentamethyl-4piperidyl) amino] -6-chloro-1,3,5-triazine condensate and the like.

Examples of organic sulfur antioxidants include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythritol-tetrakis. -(Β-lauryl-thiopropionate), ditridecyl-3,3′-thiodipropionate, 2-mercaptobenzimidazole and the like.
Examples of the organophosphorus antioxidant include trisnonylphenyl phosfte, triphenyl phosfte, tris (2,4-di-t-butylphenyl) -phosfte and the like.
Organic sulfur-based and organic phosphorus-based antioxidants are referred to as secondary antioxidants, and can provide a synergistic effect when used in combination with phenolic or amine-based primary antioxidants.

Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives.
Specific examples of the light stabilizer are shown below.
Examples of the benzophenone light stabilizer include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 2,2′-di-hydroxy-4-methoxybenzophenone. As a benzotriazole-based light stabilizer, 2-(-2′-hydroxy-5′-methylphenyl) -benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetra-hydrophthalimido-methyl) -5′-methylphenyl] -benzotriazole, 2-(-2′-hydroxy-3′-tert-butyl-5′-methylphenyl-)-5-chlorobenzo Triazole, 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl-)-5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-t-butylphenyl- ) -Benzotriazole, 2- (2′-hydroxy-5′-t-octylphenyl) -benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl) -benzotriazole, etc. Is mentioned. Other compounds include 2,4, di-t-butylphenyl-3 ′, 5′-di-t-butyl-4′-hydroxybenzoate, nickel dibutyl-dithiocarbamate, and the like.

The charge transport layer may contain at least one electron accepting substance for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, and the like.
Examples of the electron-accepting substance used in the charge transport layer in the present invention include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, Examples include o-dinitrobenzene, m-dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, and phthalic acid. Of these, fluorenone-based, quinone-based, and benzene derivatives having electron-withdrawing substituents such as Cl, CN, NO ₂ are particularly preferable.

Further, when the charge transport layer is the outermost surface layer, a tetrafluoroethylene resin or the like is included in the charge transport layer in order to improve the lubricity of the surface and / or improve the durability against toner contamination. It is also preferable to contain the fluororesin.
Below, the structural example of the electric charge transport layer at the time of adding fluororesin is shown.

Fluorine-based resins include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodifluoroethylene resin, and copolymers thereof. It is desirable to appropriately select one or two or more kinds from the above, but tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable. Specifically, product name: Fullon PTFE (Asahi Glass Co., Ltd.), product name: Fullon ETFE (Asahi Glass Co., Ltd.), product name; Kureha KF Polymer (Kureha Science Co., Ltd.), product name; Etc.
The content of the fluororesin in the charge transport layer is suitably from 0.1 to 40% by weight, particularly preferably from 1 to 30% by weight, based on the total amount of the charge transport layer. If the content is less than 1% by mass, the modification effect due to the dispersion of the fluororesin particles is not sufficient. On the other hand, if it exceeds 40% by mass, the light transmission property is lowered, and the residual potential can be increased by repeated use.
The fluororesin is preferably added in the form of particles, and the primary particle size of the fluororesin is preferably 0.05 to 1 μm, more preferably 0.1 to 0.5 μm. When the primary particle diameter is less than 0.05 μm, aggregation during dispersion tends to proceed. On the other hand, if it exceeds 1 μm, image quality defects are likely to occur.
The fluororesin can be used in combination with the above binder resin, and is a preferred embodiment.

In addition to the fluorine-based resin particles, inorganic particles may be further added.
The content of the inorganic particles in the charge transport layer is suitably from 0.1 to 30% by weight, particularly preferably from 1 to 20% by weight, based on the total amount of the charge transport layer. If the content is less than 1% by mass, the modification effect due to the dispersion of inorganic particles is not sufficient. On the other hand, if the content exceeds 30% by mass, the residual potential increases due to repeated use.
Examples of inorganic particles include alumina, silica (silicon dioxide), titanium oxide, zinc oxide, cerium oxide, zinc sulfide, magnesium oxide, copper sulfate, sodium carbonate, magnesium sulfate, potassium chloride, calcium chloride, sodium chloride, nickel sulfate. , Antimony, manganese dioxide, chromium oxide, tin oxide, zirconium oxide, barium sulfate, aluminum sulfate, silicon carbide, titanium carbide, boron carbide, tungsten carbide, zirconium carbide, one of these, or two if necessary The above is used, but silica is preferably used. The silica particles are preferably produced by a chemical flame CVD method. As a specific example, silica particles are obtained by subjecting chlorosilane gas to a gas phase reaction in a high-temperature flame of oxygen-hydrogen mixed gas or hydrocarbon-oxygen mixed gas. Is preferred.

  In addition, as the inorganic particles, particles having a hydrophobic surface are preferable. As the hydrophobizing agent, for example, a siloxane compound, a silane coupling agent, a titanium coupling agent, a polymer fatty acid or a metal salt thereof is used. Examples of the siloxane compound include polydimethylsiloxane, dihydroxypolysiloxane, octamethylcyclotetrasiloxane, and examples of the silane coupling agent include γ- (2-aminoethyl) aminopropyltrimethoxysilane and γ- (2-aminoethyl). Aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxy Silane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrime Toxisilane, p-methylphenyltrimethoxysilane and the like can be mentioned.

  The primary particle diameter of the inorganic particles is preferably 0.005 to 2.0 μm, more preferably 0.01 to 1.0 μm. If the primary particle diameter of the inorganic fine particles is less than 0.005 μm, sufficient mechanical strength on the surface of the intermediate transfer member cannot be obtained, and aggregation during dispersion tends to proceed. On the other hand, if it exceeds 2 μm, the roughness of the surface of the intermediate transfer member becomes large. When a cloning blade is used as a cleaning device, the cleaning blade is worn and damaged, and the cleaning characteristics are deteriorated. It tends to occur.

In the charge transport layer, fluorine resin particles, and further, inorganic particles can be dispersed by a media disperser such as a ball mill, a vibration ball mill, an attritor, a sand mill, a horizontal sand mill, an agitator, an ultrasonic disperser, a roll mill, Medialess dispersers such as high-pressure homogenizers can be used. Furthermore, examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high pressure state, and a penetration method in which the fine liquid is penetrated and dispersed in a high pressure state.
Examples of the dispersion of the coating liquid for forming the charge transport layer in which the releasable solid particles are dispersed include a method of dispersing fluorine resin particles and inorganic particles in a solution of a binder resin, a charge transport material and the like dissolved in a solvent. Is mentioned.

  In the present invention, it is also effective to add a small amount of a dispersion aid in order to improve the dispersion stability of the dispersion and to prevent aggregation during the formation of the coating film. Examples of the dispersion aid include fluorine-based surfactants, fluorine-based polymers, silicone-based polymers, and silicone oils. Among them, fluorine-based polymers, in particular, fluorine-based comb-type graft polymers are effective as a dispersion aid, and examples of fluorine-based comb-type graft polymers include macromonomers composed of acrylic ester compounds, methacrylic ester compounds, styrene compounds, and the like. A resin graft-polymerized from perfluoroalkylethyl methacrylate is preferred.

[Underlayer]
The undercoat layer in the present invention is a layer provided between the substrate 110 and the charge generation layer 124 as shown in FIGS. 5A, 5B, 5C, and 4D, It plays the role of an electrical blocking layer and the role of improving the wettability with the charge generation layer as the upper layer.
Such an undercoat layer is composed of acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride. -Organic metals containing zirconium, titanium, aluminum, manganese, silicon atoms, etc. in addition to polymer resin compounds such as vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin Formed from materials such as compounds. These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds.
Among them, an organometallic compound containing a zirconium atom or a silicon atom is excellent in performance such as a low residual potential, a small potential change due to the environment, and a small potential change due to repeated use. The organometallic compound can be used alone or in combination, or mixed with the above-described resin.

Examples of organometallic compounds containing silicon atoms include, for example, vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ -Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β -(Aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, and the like.
Among these, particularly preferably used silicon compounds are vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, Examples include silane coupling agents such as N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

  Examples of organometallic compounds containing a zirconium atom include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, Zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of organometallic compounds containing titanium atoms include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, Examples include titanium lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

  Examples of the organometallic compound containing an aluminum atom include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  In the case of the undercoat layer in the present invention, when the film thickness is too large, the electrical barrier becomes too strong, causing desensitization and an increase in potential due to repetition. Therefore, in the case of forming the undercoat layer having the above-described configuration, the film thickness range is set to 0.1 to 3 μm.

[Surface protective layer]
In the present invention, it is also possible to form a surface protective layer on the charge transport layer for the purpose of improving the wear resistance of the intermediate transfer member and extending its life or preventing chemical change of the charge transport layer. It is. In the case of providing a surface protective layer, it is preferable to use the above-mentioned fluorine-based resin for the surface protective layer because durability against toner contamination is increased. The fluororesin that can be used for the surface protective layer is the same as that described for the charge transport layer, and the preferred fluororesin is also the same. One type or two or more types of fluororesins can be used in combination. In addition, the fluororesin can be used in combination with the following insulating resin and charge transporting polymer compound.
When using a fluororesin, it is preferable that the content rate of a fluororesin is 0.1-40 mass% with respect to the whole surface protective layer, More preferably, it is 1-30 mass%. If the content is less than 0.1% by mass, the modification effect due to the dispersion of the fluororesin particles is not sufficient. On the other hand, if the content exceeds 40% by mass, the light transmission property decreases and the residual potential increases due to repeated use. .

  Examples of the surface protective layer include (1) an insulating surface protective layer made of an insulating resin, (2) a resistance control type surface protective layer in which a resistance control agent such as a metal oxide is dispersed, and (3) charge transportability. Examples thereof include a charge transporting surface protective layer made of a given polymer compound.

  Examples of the insulating resin used for the insulating surface protective layer made of an insulating resin include polyamide resins, polyurethane resins, polyester resins, epoxy resins, polyketone resins, polycarbonate resins, and other condensation resins, polyvinyl ketone resins, polystyrene resins, and polyacrylamides. Vinyl polymers such as resins can be raised.

Next, the resistance control type surface protective layer in which the resistance control agent is dispersed will be described.
As the resistance control agent, particles of carbon black, metal, metal oxide or the like can be used. The particle diameter is preferably 100 nm or less.
Examples of metal oxides include titanium oxide, zinc oxide, tin oxide, antimony oxide coated tin oxide, silicon oxide, iron oxide, aluminum oxide, cerium oxide, yttrium oxide, silicon oxide, zirconium oxide, iron oxide, magnesium oxide, oxidation Copper, manganese oxide, molybdenum oxide, tungsten oxide, solid solution of barium sulfate and antimony oxide, mixture of the above metal oxides, titanium oxide, tin oxide, zinc oxide or barium sulfate in a single particle The thing mixed and the thing which coat | covered said metal oxide to the single particle of a titanium oxide, a tin oxide, zinc oxide, or barium sulfate is mentioned.
Further, metallocene compounds such as N, N′-dimethylferrocene, N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine, etc. An aromatic amine compound or the like can be used as a resistance control agent (particle) adjuster.
Furthermore, these metal oxides can be surface-treated with organic compounds such as silane coupling agents, titanium coupling agents, and zirconium coupling agents to improve various properties such as dispersibility, if necessary. .

  Among these, it is preferable to use a metal oxide having a particle size of 100 nm or less for the resistance control type surface protective layer. Thereby, the resistance control type surface protective layer is rich in transparency, and even if a thick film is formed, the decrease in the transmittance is small, so that the decrease in sensitivity can be suppressed. Therefore, in addition to the high wear resistance strength, it is possible to further improve the life of the intermediate transfer member in combination with the effect of increasing the film thickness.

Resistance control type surface protective layer is acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, A film is formed by dispersing the above resistance control agent (particles) in a binder resin such as vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, melamine resin. .
The resistance control agent is dispersed in the binder resin to form a film, but the addition amount of the resistance control agent is adjusted in order to obtain an appropriate coating film resistance. As the addition amount of the resistance control agent, 10 to 60% by volume, preferably 20 to 50% by volume is contained in the binder resin solid content.

Subsequently, a charge transporting surface protective layer made of a polymer compound imparted with charge transporting property will be described.
As the charge transporting surface protective layer, a polymer compound having a charge transporting property in the molecule (hereinafter sometimes referred to as a charge transporting polymer compound) or a tough material such as a silicone hard coat agent is used. A resin component having a charge transporting function by dispersing a low-molecular charge transporting agent in the coating agent at the molecular level can be used.
Examples of the charge transporting polymer compound include those in which a charge transporting group is added in the molecule of the silicone polymer. In addition, a polymer compound containing a group having a charge transport ability such as polyvinylcarbazole in the side chain, a polymer containing a group having a charge transport ability as disclosed in JP-A-5-232727, etc. in the main chain A compound, polysilane, etc. can also be mentioned.
In addition, as the charge transporting polymer compound, a block copolymer or a graft copolymer composed of a charge transporting block and an insulating block can be used. When the charge transporting polymer compound contains a triarylamine structure as a repeating unit, it is preferable because it has a high charge transporting ability and favorable mechanical properties, and the triarylamine structure is not a pendant type, More preferably, it is contained in the main chain. In the case of the pendant type, pendants are often associated with each other to form charge traps and deteriorate the charge transport property, but such problems can be avoided by being contained in the main chain.
Furthermore, when the charge transporting polymer compound contains a triarylamine structure in the main chain, the structure represented by the following general formula (1) or (2) in the main chain It is preferable that a triarylamine structure containing at least one of the above as a repeating unit is contained.

However, in the general formula (1), Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aryl group, and X ¹ is a divalent hydrocarbon group having an aromatic ring structure or 2 containing a hetero atom. A divalent hydrocarbon group, X ² and X ³ each independently represent a substituted or unsubstituted arylene group, and L ¹ may contain a divalent hydrocarbon group or a heteroatom which may contain a branched or ring structure Represents a hydrocarbon group, and m and n each represents an integer selected from 0 or 1;

However, in General Formula (2), Ar ³ and Ar ⁴ each independently represent a substituted or unsubstituted aryl group, and L ² represents a trivalent hydrocarbon group or heteroatom-containing hydrocarbon group having an aromatic ring structure. Indicates.

In the general formula (1), Ar ¹ and Ar ² are each independently selected from a substituted or unsubstituted aryl group. Specific examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, and a pyrenyl group. Is mentioned. Examples of the substituent include a methyl group, an ethyl group, a methoxy group, and a halogen atom.

X ¹ is selected from a divalent hydrocarbon group having an aromatic ring structure or a divalent hydrocarbon group containing a hetero atom. Specific examples of X ¹ include a phenylene group, a biphenylene group, a terphenylene group, a naphthylene group, a methylenediphenyl group, a cyclohexylidenediphenyl group, an oxydiphenyl group, a thiodiphenyl group, and the like, and methyl-substituted products and ethyl-substituted products thereof. In particular, a substituted or unsubstituted biphenylene group is particularly preferable from the viewpoint of charge transportability.

X ² and X ³ are each independently selected from a substituted or unsubstituted arylene group, specifically, a phenylene group, a biphenylene group, a terphenylene group, a naphthylene group, and the like, and methyl-substituted, ethyl-substituted, A methoxy substituted body, a halogen substituted body, etc. are mentioned.

L ¹ is selected from a divalent hydrocarbon group or a heteroatom-containing hydrocarbon group which may contain a branched or ring structure, and is optional as long as it exhibits at least one of the above-mentioned preferable characteristics. And those having a bonding group selected from an ester bond, a carbonate bond, a siloxane bond and the like and having 20 or less carbon atoms. Specific examples of L ¹ include divalent compounds represented by the following formulas (3-1) to (3-9).

In the general formula (2), Ar ³ and Ar ⁴ are each independently selected from a substituted or unsubstituted aryl group. Specific examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, and a pyrenyl group. Can be mentioned. Moreover, as a substituent, a C1-C12 alkyl group or an alkoxy group, a diarylamino group, a halogen atom, etc. are mentioned.

L ² is selected from a trivalent hydrocarbon group having an aromatic ring structure or a heteroatom-containing hydrocarbon group, and may be any one as long as it exhibits at least one of the above preferred characteristics, but has a carbon number of 20 or less Is preferred. Specific examples thereof include those represented by the following formulas (3-10) to (3-14).

The case where L ¹ in the general formula (1) or L ² in the general formula (2) has an ester bond is particularly preferable in terms of mechanical properties and charge transport ability.

  As a binder resin when using this charge transporting polymer compound, polyamide resin, polyvinyl acetal resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, Known resins such as a polyimide resin and a polyamideimide resin can be used. These can also be used by cross-linking each other as necessary.

  Here, the surface protective layer in the present invention is preferably made of a resin having a certain degree of hardness in order to prevent the conductive foreign matter penetrating into the intermediate transfer member from the outside with the surface protective layer. Specifically, the Vickers hardness is preferably 30 or more.

  The surface protective layer is formed by preparing a coating solution containing the components used in each of the surface protective layers described above, and applying and drying it. The method of dispersing and blending the resistance control agent and the charge transporting polymer compound is the same as the method for forming the charge transport layer described above.

The thickness of the surface protective layer is preferably 0.1 to 20 μm, more preferably 1 to 10 μm. Coating methods of the coating solution for forming this surface protective layer include blade coating method, wire bar coating method, spray coating method, dip coating method, ring coating method, bead coating method, air knife coating method, curtain coating method. A usual method such as can be used.
Moreover, as a solvent used for the coating liquid for forming the surface protective layer, a normal organic solvent such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene, alcohol or the like may be used alone or in combination. However, it is preferable to use a solvent that hardly dissolves the photosensitive layer to which the coating solution is applied.

[Base material]
Next, the base material constituting the intermediate transfer member of the present invention will be described.
There is no restriction | limiting in particular in the shape in the base material in this invention, It can comprise in the shape of a belt or a drum.

  The base material in the present invention is not particularly limited as long as it is a resin material that can satisfy the mechanical properties of Young's modulus of 2000 MPa or more from the viewpoint of color registration (color shift).

The base material in the present invention is preferably semiconductive having a volume resistivity of 1 × 10 ⁶ to 1 × 10 ¹³ Ωcm, and more preferably 1 × 10 ⁹ to 1 × 10 ¹² Ωcm. It is. When the volume resistivity of the base material is less than 1 × 10 ⁶ Ωcm, when this intermediate transfer member is applied to a tandem image forming apparatus described later, the resistance between each color of the primary transfer is low, so that the transfer portion In some cases, the necessary transfer voltage cannot be applied. Further, if it exceeds 1 × 10 ¹³ Ωcm, there may be a problem that the charge cannot be sufficiently removed.
In particular, when the photoconductive layer of the present invention is used, the efficiency of transfer and static elimination differs significantly depending on the relationship between the volume resistivity of unirradiated and irradiated and the volume resistivity of the substrate. It is important to adjust the volume resistivity.

Further, the surface resistivity of the substrate is preferably 1 × 10 ^{10 to} 3 × 10 ¹³ Ω / □, and more preferably 5 × 10 ¹⁰ to 1 × 10 ¹³ Ω / □.
Further, the volume resistivity of the substrate is preferably 1 × 10 ⁸ to 1 × 10 ¹³ Ω / cm, and more preferably 1 × 10 ⁹ to 1 × 10 ¹² Ωcm.
In addition, the measuring method of the volume resistivity and surface resistivity of a base material can apply the measuring method of the volume resistivity and surface resistivity of an intermediate transfer body in description of a surface layer.

  Examples of the resin material used for the base material include polyimide resin, polyamideimide resin, fluorine resin, vinyl chloride vinyl acetate copolymer, polycarbonate (PC), polyethylene terephthalate (PET), vinyl chloride resin, ABS resin, Examples thereof include polyester resins such as polymethyl methacrylate (PMMA) and polybutylene terephthalate (PBT), and polyamide (PA). These may be used alone or in combination of two or more. Among these, the polyimide resin is preferable in that it is not affected by the drying temperature when the above-described charge transport layer, charge generation layer, and undercoat layer are coated and dried, and is excellent in both structural strength and bending fatigue. Used for.

Examples of the polyimide resin are those obtained by reacting an aromatic tetracarboxylic acid component and an aromatic diamine component in an organic polar solvent. As aromatic tetracarboxylic acid components, pyromellitic acid, naphthalene-1,4,5,8-tetracarboxylic acid, naphthalene-2,3,6,7-tetracarboxylic acid, 2,3,5,6-biphenyl Tetracarboxylic acid, 2,2 ′, 3,3′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-diphenylethertetracarboxylic acid Acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, 3,3 ′, 4,4′-azobenzenetetracarboxylic acid, bis ( 2,3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane, β, β-bis (3,4-dicarboxyphenyl) propane, β, β-bis (3,4-dicarboxy) Phenyl) Kisa has full Oro propane or a mixture of these tetracarboxylic acids. The aromatic diamine component is not particularly limited, and m-phenyldiamine, p-phenyldiamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,4-diaminochlorobenzene, m-xylylenediamine P-xylylenediamine, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4′-diaminonaphthalenediphenyl, benzidine, 3,3-dimethylbenzidine, 3,3 '-Dimethoxybenzidine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether (oxy-p, p'-dianiline; ODA), 4,4'-diaminodiphenyl sulfide, 3, 3′-diaminobenzophenone, 4,4′-diaminophenyl sulfone, 4,4′-diaminoazobenzene, , 4'-diaminodiphenylmethane, beta, beta-bis (4-amine phenyl) propane.
Examples of the organic polar solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphortriamide and the like. These organic polar solvents can be mixed with phenols such as cresol, phenol, and xylenol, and hydrocarbons such as hexane, benzene, and toluene as necessary. Used as a mixture of more than one kind.
It is a preferable aspect that the substrate in the present invention is composed of a polyimide resin obtained by dispersing the following conductive agent and has the above-described volume resistivity.

(Conductive agent)
In order to obtain the above-described volume resistivity (electrical resistance), the base material in the present invention includes one or more kinds of conductive agents imparting electron conductivity and conductive agents imparting ionic conductivity as necessary. Add in combination.

As an electron conductive conductive agent, metal or alloy such as carbon black, graphite, aluminum, nickel, copper alloy, tin oxide, zinc oxide, kalim titanate, tin oxide-indium oxide or tin oxide-antimony oxide composite oxide, etc. And metal oxides. Examples of the ion conductive conductive agent include sulfonates and ammonia salts, and various surfactants such as cationic, anionic, and nonionic surfactants.
Furthermore, there is a method of blending conductive polymers. Examples of the conductive polymer include various (for example, styrene) copolymers with (meth) acrylates that bind a quaternary ammonium base to a carboxyl group, and a quaternary ammonium base. Polymers that bind quaternary ammonium bases, such as a copolymer of maleimide and methacrylate, which binds to styrene, polymers that bind alkali metal salts of sulfonic acids such as sodium polysulfonate, hydrophilic units of at least alkyl oxide in the molecular chain For example, polyethylene oxide, polyethylene glycol-based polyamide copolymer, polyethylene oxy-epichlorohydrin copolymer polyether amide imide, block type polymer having polyether as a main segment, further polyaniline, Li thiophene, can be exemplified polyacetylene, polypyrrole, polyphenylene vinylene and the like, can be used these conductive polymers undoped state, or in a doped state. The above-described electrical resistance can be stably obtained by using one or two or more of the above-mentioned conductive agent, conductive polymer, or surfactant.

  The conductive agent in the present invention has good dispersibility in the resin composition, good dispersion stability is obtained, resistance variation can be reduced, electric field dependency is also reduced, and further, depending on the transfer voltage. Acidic carbon black having a pH of 5 or less is preferred because the electric field concentration is less likely to improve the stability of electrical resistance over time.

-Acidic carbon black of pH 5 or less-
Acidic carbon black having a pH of 5 or less can be produced by oxidizing carbon black to give a carboxyl group, a quinone group, a lactone group, a hydroxyl group, or the like. This oxidation treatment is an air oxidation method in which contact is made with air in a high-temperature atmosphere to react, a method of reacting with nitrogen oxides or ozone at room temperature, and air oxidation at high temperature, followed by ozone oxidation at a low temperature. It can be performed by a method or the like. Specifically, acidic carbon black having a pH of 5 or less can be produced by a contact method. Examples of the contact method include a channel method and a gas black method. Acidic carbon black can also be produced by a furnace black method using gas or oil as a raw material. Further, if necessary, after performing these treatments, a liquid phase oxidation treatment with nitric acid or the like may be performed. Acidic carbon black can be produced by a contact method, but is usually produced by a closed furnace method. In the furnace method, usually only carbon black having a high pH and a low volatile content is produced, but the pH can be adjusted by subjecting it to the above-mentioned liquid phase acid treatment. For this reason, in the present invention, carbon black obtained by furnace method production and adjusted to have a pH of 5 or less by post-treatment is considered to be included in acidic carbon black having a pH of 5 or less.

  The pH value of the acidic carbon black in the present invention is preferably pH 5.0 or less, more preferably pH 4.5 or less, and further preferably pH 4.0 or less. Acidic carbon having a pH of 5.0 or less has an oxygen-containing functional group such as a carboxyl group, a hydroxyl group, a quinone group, and a lactone group, so that the dispersibility in the resin is good and good dispersion stability is obtained. The variation in resistance of the transfer body can be reduced, and the electric field dependency is also reduced, so that the electric field concentration due to the transfer voltage is less likely to occur.

  The pH of the carbon black is determined by adjusting an aqueous suspension and measuring with a glass electrode. Further, the pH of the carbon black can be adjusted by conditions such as the treatment temperature and treatment time in the oxidation treatment step.

The oxidized carbon black having a pH of 5.0 or less preferably has a volatile component content of 1 to 25% by mass, more preferably 3 to 20% by mass, and 3.5 to 15% by mass. More preferably. When the content of the volatile component is less than 1% by mass, the effect of the oxygen-containing functional group attached to the outside is lost, and the dispersibility in the binder resin may be reduced. On the other hand, when the content of the volatile component is higher than 25% by mass, it may be decomposed when dispersed in the resin composition, or the amount of water adsorbed on the outside oxygen-containing functional group may increase. The appearance of the substrate in the present invention may be deteriorated.
On the other hand, the dispersion | distribution in the said resin composition can be made more favorable because content of the said volatile component shall be 1-25 mass%. The content of the volatile component can be determined from the ratio of organic volatile components (carboxyl group, hydroxyl group, quinone group, lactone group, etc.) that appear when carbon black is heated at 950 ° C. for 7 minutes.

  The substrate in the intermediate transfer member of the present invention may contain two or more types of carbon black. At that time, these carbon blacks are preferably substantially different in conductivity from each other, for example, those having different physical properties such as degree of oxidation treatment, DBP oil absorption, specific surface area by BET method utilizing nitrogen adsorption, etc. Use. Thus, when adding two or more types of carbon blacks having different electrical conductivity, for example, after adding carbon black that exhibits high electrical conductivity preferentially, carbon black with low electrical conductivity is added to increase the surface resistivity. It is possible to adjust. Even when two or more types of carbon black are contained in this way, at least one of them can be mixed and dispersed by using an oxidation-treated carbon black having a pH of 5.0 or less.

  Specific examples of acidic carbon black having a pH of 5.0 or less include “Printex 150T” (pH 4.5, volatile content 10.0% by mass) and “Special Black 350” (pH 3.5, volatile) manufactured by Degussa. 2.2% by mass), “Special Black 100” (pH 3.3, volatile content 2.2% by mass), “Special Black 250” (pH 3.1, volatile content 2.0% by mass), “ Special Black 5 ”(pH 3.0, volatile content 15.0% by mass),“ Special Black 4 ”(pH 3.0, volatile content 14.0% by mass),“ Special Black 4A ”(pH 3.0, volatile) 14.0% by mass), “Special Black 550” (pH 2.8, volatile content 2.5% by mass), “Special Black 6” (pH 2.5, volatile content 18.0% by mass), “ Carabu FW200 "(pH 2.5, volatile content 20.0% by mass)," Color Black FW2 "(pH 2.5, volatile content 16.5% by mass)," Color Black FW2V "(pH 2.5, volatile) 16.5% by mass), “MONARCH1000” manufactured by Cabot (pH 2.5, volatile content 9.5% by mass), “MONARCH 1300” manufactured by Cabot (pH 2.5, volatile content 9.5% by mass), Cabot Corporation “MONARCH1400” (pH 2.5, volatile matter 9.0% by mass), “MOGUL-L” (pH 2.5, volatile matter 5.0% by mass), “REGAL400R” (pH 4.0, volatile matter 3) 0.5 mass%) and the like.

  The acidic carbon black having a pH of 5.0 or less is more conductive than the general carbon black because it has better dispersibility in the resin composition due to the effect of the oxygen-containing functional group present on the surface as described above. It is preferable to increase the addition amount as a powder. Thereby, since the amount of carbon black in the base material increases, the effect of using the oxidized carbon black that can suppress the in-plane variation of the electric resistance value can be maximized.

  As content of the said acidic carbon black below pH5.0 with respect to the base material in this invention, what is necessary is just to satisfy said preferable volume resistivity (electrical resistance), Specifically, it is 10-30 mass%. In this case, the effect of acidic carbon black, such as suppressing in-plane variation in the surface resistivity of the intermediate transfer member, can be exhibited, which is preferable. If the acidic carbon black having a pH of 5.0 or less is less than 10% by mass, the uniformity of electrical resistance is lowered, and the in-plane unevenness of the surface resistivity and the electric field dependency may increase. On the other hand, if the content of the oxidized carbon black having a pH of 5.0 or less exceeds 30% by mass, it may be difficult to obtain a desired resistance value. Further, it is more preferable to contain 18-30% by mass of the oxidized carbon black having a pH of 5.0 or less. By containing 18-30% by mass of the oxidized carbon black having a pH of 5.0 or less, the effect is maximized. It is possible to achieve the limit, and it is possible to reduce in-plane resistance unevenness and electric field dependency.

[Middle layer]
In the present invention, an intermediate layer can be provided between the substrate and the surface layer. The intermediate layer is not particularly limited, but the intermediate layer is particularly preferably an elastic layer having a function of controlling the elasticity of the intermediate transfer member itself. Hereinafter, a case where an intermediate layer functioning as an elastic layer is provided will be described in more detail.
The intermediate layer preferably has a hardness of 30 to 60 °, more preferably 35 to 55 ° in terms of JIS-A hardness. By having the intermediate layer having such hardness, the intermediate transfer member itself can be adjusted so that the hardness of the intermediate transfer member itself is 40 to 60 ° in terms of JIS-A hardness.
Here, the JIS-A hardness in the present invention refers to a hardness based on JIS K 6253 (1997). In the present invention, the JIS-A hardness of the intermediate layer can be measured using a durometer type A manufactured by Shimadzu Corporation in accordance with JIS K 6253 (1997). In addition, a sheet-like sample was used for the measurement. The same applies when measuring the JIS-A hardness of the intermediate transfer member itself.
Moreover, the thickness of the intermediate layer in the present invention is preferably in the range of 0.01 to 2 mm, more preferably in the range of 0.05 to 0.5 mm.

The material constituting the intermediate layer in the present invention is not particularly limited as long as the JIS-A hardness satisfies the above range and has a volume resistivity equivalent to that of the substrate described later. The hardness and volume resistivity can be adjusted by the selection of the following rubber materials and the addition amount of a conductive agent, a low molecular weight component and the like. Specifically, rubbers such as nitrile rubber, ethylene propylene rubber, chloroprene rubber, isoprene rubber, styrene rubber, butadiene rubber, butyl rubber, chlorosulfonated polyethylene, urethane rubber, epichlorohydrin rubber, acrylic rubber, silicone rubber, fluorine rubber, etc. Examples of the material include a material in which a conductive agent is dispersed.
As the conductive agent, a conductive agent imparting electron conductivity or a conductive agent imparting ionic conductivity can be added singly or in combination of two or more.
As an electron conductive conductive agent, metal or alloy such as carbon black, graphite, aluminum, nickel, copper alloy, tin oxide, zinc oxide, kalim titanate, tin oxide-indium oxide or tin oxide-antimony oxide composite oxide, etc. And metal oxides. Examples of the ion conductive conductive agent include sulfonates and ammonia salts, and various surfactants such as cationic, anionic, and nonionic surfactants.
These rubber materials and conductive agents can be used alone or in admixture of two or more.

In addition, it is preferable to use a liquid rubber material as these rubber materials. By using the liquid rubber material, the wettability with the upper surface layer is improved, and there is no need to interpose an adhesive layer described later. Thus, the layer configuration can be simplified, which is very advantageous in producing the intermediate transfer member used in the present invention. Moreover, it is similarly advantageous in terms of cost.
The formation of the intermediate layer using such a liquid rubber material is usually performed by applying the liquid rubber material in which a conductive agent such as carbon black is dispersed as it is or adjusting the viscosity with an appropriate solvent on the intermediate layer. Application, baking and vulcanization can be performed.

When a rubber material other than the liquid rubber material is used, the intermediate layer can be formed as follows.
First, a material obtained by adding a conductive agent such as carbon black to the raw rubber material is kneaded using a kneader such as Banbury. The kneaded material is pressed to form a rubber sheet. The intermediate layer is formed by vulcanization and adhesion in a state where the rubber sheet is wound on the intermediate layer described above.

[Adhesive layer]
Next, the adhesive layer will be described. The adhesive layer is a layer that can be provided as necessary between the above-described intermediate layer and the surface layer, and plays a role in improving the wettability between the surface layer and the intermediate layer. The adhesive layer can also serve as an electrical blocking layer.

  Such an adhesive layer is composed of acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride In addition to polymer resin compounds such as vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, organometallic compounds containing zirconium, titanium, aluminum, manganese, silicon atoms, etc. Formed from such materials. These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds. Among them, an organometallic compound containing a zirconium atom or a silicon atom is excellent in performance such as a low residual potential, a small potential change due to the environment, and a small potential change due to repeated use. The organometallic compound can be used alone or in combination, or mixed with the above-described resin.

  In the adhesive layer according to the present invention, when the film thickness is too large, the electric barrier becomes too strong, causing desensitization and potential increase due to repetition. Therefore, when the adhesive layer having the above-described configuration is formed, the film thickness is preferably set in the range of 0.1 to 3 μm. A more preferable film thickness is 0.2 to 2 μm.

[Surface micro hardness of intermediate transfer member]
In the intermediate transfer member of the present invention, when a surface layer or a surface protective layer is provided, the surface protective layer, that is, the outermost layer has a surface microhardness of preferably 30 degrees or less, more preferably 25 degrees or less. preferable. The present inventors have found that there is a very accurate correlation between the surface microhardness of the outermost layer and the generation level of the holocharacter. That is, when the surface microhardness of the outermost layer is 30 degrees or less, more preferably 25 degrees or less, the intermediate transfer member of the present invention has a transfer surface by the pressing force of the bias roller when used in an image forming apparatus described later. As a result, the pressing force concentrated on the semiconductive toner is dispersed. For this reason, the toner does not aggregate, and image quality defects such as a holocharacter in which the line image disappears are not generated.

The surface microhardness can be determined by a method of measuring how much the indenter has entered the sample. A method for measuring the surface microhardness will be described.
FIG. 7 is a schematic diagram showing the measurement principle of the surface microhardness of the surface layer. In FIG. 7, 150 represents a needle-like indenter, 152 represents a surface layer, and an arrow P represents a load applied to the needle-like indenter 150. means.
In measuring the surface microhardness, the tip of the needle-shaped indenter 150 having a predetermined shape is pressed onto the outermost surface portion of the surface layer 12 until the load L (mN) is changed from the load 0 to the predetermined load P. When the depth of penetration of the needle-like indenter 150 into the surface layer 12 in the vertical direction is D (μm), the surface microhardness DH is expressed by the following formula (4).
Formula (4); DH≡αP / D ²
Here, α in equation (4) is a constant depending on the shape of the indenter, and α = 3.8854 (indenter used: in the case of a triangular pyramid indenter).

  This surface microhardness is the hardness obtained from the excessive weight and indentation depth in the process of indenting the indenter, and represents the strength characteristics of the material including not only plastic deformation of the sample but also elastic deformation. is there. In addition, the measurement area is very small, and more accurate hardness measurement is possible within a range close to the toner particle diameter.

The surface microhardness of the outermost layer is determined by the following method. A sheet of material (surface layer material) constituting the intermediate transfer member is cut into about 5 mm square, and the small piece is fixed to the glass plate with an instantaneous adhesive. The surface microhardness of the outermost layer surface of this sample is measured using an ultra microhardness meter DUH-201S (manufactured by Shimadzu Corporation). The measurement conditions are as follows.
Measurement environment: 23 ° C, 55% RH
Working indenter: Triangular pyramid indenter Test mode: 3 (soft material test)
Test load: 6.9 × 10 ⁻³ N (0.70 gf)
Load speed: 0.142 × 10 ⁻³ N (0.0145 gf / sec)
Holding time: 5 sec

[Volume resistivity and surface resistivity of intermediate transfer member]
The volume resistivity of the intermediate transfer member at the time of light irradiation is preferably 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm, more preferably 1 × 10 ⁹ to 1 × 10 ¹² Ωcm. It is preferably 1 × 10 ¹³ to 1 × 10 ¹⁵ Ωcm, and more preferably 1 × 10 ^13.5 to 1 × 10 ^14.5 Ωcm. The surface resistivity of the intermediate transfer member is preferably 1 × 10 ¹³ to 1 × 10 ¹⁵ Ω / □, and more preferably 1 × 10 ^13.5 to 1 × 10 ^14.5 Ω / □.

[Thickness of intermediate transfer member]
When the intermediate transfer member of the present invention is used as an intermediate transfer belt, the total thickness is preferably in the range of 0.03 to 1.0 mm, and in the range of 0.05 to 0.8 mm. More preferably, it is still more preferably in the range of 0.1 to 0.5 mm.
When the total thickness is less than 0.03 mm, belt expansion / contraction (displacement amount) due to disturbance (load fluctuation) during driving of the belt increases, and it may be impossible to stably obtain good image quality. On the other hand, when the total thickness exceeds 1.0 mm, the deformation amount of the outer surface of the belt at a belt bending portion such as a drive system roll becomes large, and a good image quality may not be obtained. Further, the deformation amount between the outer side and the inner side of the belt increases, and there may be a problem that the belt breaks due to local repeated stress.

  The thickness of the surface layer (photoconductive layer) is preferably in the range of 10 to 80% of the total thickness of the intermediate transfer member, and more preferably in the range of 20 to 60%. Moreover, when providing a surface protective layer, it is preferable that the thickness of a surface protective layer is in the range of 0.1 to 5% of the total thickness of the surface layer, and more preferably in the range of 1 to 3%. preferable.

<Image forming method>
In the present invention, the image forming method is not particularly limited as long as the intermediate transfer member of the present invention is used.
For example, as described in Japanese Patent Application Laid-Open No. 7-146616, between the primary transfer and the secondary transfer, the primary transfer toner image is irradiated with light, and the primary transfer toner is neutralized to easily perform the secondary transfer. A method may be employed, or as described in JP-A-5-257398, a method may be employed in which light is irradiated from the back surface of the intermediate transfer member at the time of primary transfer to facilitate primary transfer.
Alternatively, a method of neutralizing the intermediate transfer member by irradiating with light may be employed.
In any case, it is preferable to use a change in conductivity caused by light irradiation of the intermediate transfer member. More preferably, the method includes a step of discharging the light by irradiating at least the intermediate transfer member after the secondary transfer.

  In the light irradiation for neutralizing the intermediate transfer member, the light source to be used is not particularly limited as long as the volume resistivity of the photoconductive layer is changed by the light irradiation. In order to efficiently use the photoconductivity of the contained fullerene, it is preferable to use a red light LED (Light Emitting Diode), an LD (Laser Diode), or the like.

  In addition, in the image forming method using the intermediate transfer member of the present invention, ordinary methods can be applied to other processes such as a charging method and a transfer method.

<Image forming apparatus>
The image forming apparatus of the present invention is an intermediate transfer body type image forming apparatus, and uses the above-described intermediate transfer body of the present invention as the intermediate transfer body, and transfers a toner image formed on the surface of the intermediate transfer body to a transfer material. The other configuration is not particularly limited as long as it includes a light neutralizing unit that neutralizes the surface of the intermediate transfer member by light irradiation after the transfer. For example, a normal monocolor image forming apparatus that contains only a single color toner in the developing device, or a color image in which a toner image carried on an image carrier such as a photosensitive drum is repeatedly subjected to primary transfer sequentially to an intermediate transfer member Any of a forming apparatus, a tandem type color image forming apparatus in which a plurality of image carriers having developing units for respective colors are arranged in series on an intermediate transfer member may be used.
The image forming apparatus of the present invention may be configured to include a plurality of intermediate transfer members. In that case, in the image forming apparatus of the present invention, at least one of the plurality of intermediate transfer members may be the above-described intermediate transfer member of the present invention, and all are preferably the intermediate transfer member of the present invention.

  In the present invention, the term “transfer material” refers to an intermediate transfer member used for transferring a toner image on the surface of an intermediate transfer member indirectly to a recording material such as recording paper or an OHP sheet, or when transferring directly. It means both of the recording materials used in the above. Accordingly, the image forming apparatus of the present invention has a plurality of intermediate transfer members that transfer the toner image formed on the surface of the intermediate transfer member of the present invention to another intermediate transfer member (transfer material), for example. May be provided. Also in this case, in the image forming apparatus of the present invention, at least one of the plurality of intermediate transfer members may be the above-described intermediate transfer member of the present invention, and all are preferably the intermediate transfer member of the present invention.

In the image forming apparatus of the present invention, it is preferable to provide a cleaning unit for cleaning the outer peripheral surface of the intermediate transfer member after static elimination. Such a cleaning means preferably has a structure of a first cleaning means and a second cleaning means described below.
The first cleaning means includes one or more cleaning units including a brush member that contacts the outer peripheral surface of the intermediate transfer member, and a voltage is applied to the brush member when the outer peripheral surface of the intermediate transfer member is cleaned. It is.
The second cleaning means includes a cleaning blade that contacts the outer peripheral surface of the intermediate transfer member.

When an image is formed using an image forming apparatus having such a cleaning unit, the toner image is prevented from being scattered, and the intermediate transfer member after the secondary transfer is performed even if a toner having a smaller diameter and a substantially spherical shape is used. The toner remaining on the surface is excellent in cleaning property, and a high-quality image can be stably formed.
Hereinafter, the cleaning unit according to the present invention will be described in more detail by dividing it into a first cleaning unit and a second cleaning unit.

[First cleaning means]
As described above, the first cleaning unit includes at least one cleaning unit including a brush member that abuts the outer peripheral surface of the intermediate transfer member. When the outer peripheral surface of the intermediate transfer member is cleaned, a voltage is applied to the brush member. The cleaning means is not particularly limited as long as it is applied.
However, it is more preferable that the first cleaning means has a configuration as described below.

  First, as a cleaning unit, it is preferable to have a conductive roll in contact with the brush member and a blade disposed in contact with the conductive roll in addition to the brush member. As a result, the residual toner on the surface of the intermediate transfer body collected by the brush member can be further transferred from the brush member to the conductive roll, and the residual toner adhering to the surface of the conductive roll can be peeled off and collected by the blade. Residual toner accumulates on the brush member, and the cleaning performance is unlikely to deteriorate.

The brush member is preferably formed by implanting fibers in the radiation direction and forming the outer shape in a cylindrical shape. The fiber applied to the brush member is preferably a conductive fiber, and the electrical resistance is more preferably about 1 × 10 ⁰ to 1 × 10 ⁶ Ω, and further preferably 1 × 10 ² to 1 ×. 10 ⁵ Ω.
The material of the fiber is preferably conductive nylon, acrylic fiber to which conductive particles (conductive carbon black or the like) are added, nylon fiber, polypropylene fiber, polyester fiber, or the like, more preferably acrylic fiber.
The thickness of the fiber is preferably about 8 to 25 μm. Planted bristle density of the ^{fibers, 1 × 10 3 ~1 × 10} 4 present / cm ² is preferably about.

The brush member is preferably attached to the intermediate transfer member so as to bite 1 to 3 mm, more preferably 1.2 to 2 mm. The rotation speed of the brush member is preferably 40 to 180 mm / s, more preferably 50 to 80 mm / s.
The voltage applied to the brush member is preferably +100 to +600 V, more preferably +150 to +400 V.

The electric resistance of the conductive roll is more preferably 1 × 10 ⁷ to 1 × 10 ⁹ Ω, and further preferably 1 × 10 ⁸ to 1 × 10 ⁹ Ω. The conductive roll is preferably made of a metal core coated with a polyimide resin, a resin core coated with a polyimide resin, or the like, more preferably a metal core coated with a polyimide resin. The thickness of the polyimide resin coating film is preferably about 0.03 to 0.06 mm.

It is preferable that a conductive roll is attached so that it may bite into a brush member 1-3 mm, More preferably, it is 1.2-2 mm. The rotational speed of the conductive roll is preferably 40 to 180 mm / s, more preferably 50 to 100 mm / s.
The voltage applied to the conductive roll is preferably +300 to +1000 V, more preferably +400 to +800 V.

  The material of the blade in contact with the conductive roll is preferably stainless steel or bronze, and more preferably stainless steel. It is preferable to abut on the conductive roll at an abutment angle of 10 to 80 degrees, and more preferred to abut at 20 to 60 degrees. The amount of biting of the blade into the conductive roll at this time is preferably 0.2 to 2 mm.

One or more cleaning units can be arranged in series along the rotation direction of the intermediate transfer member.
In this case, in order to enhance the cleaning effect of the residual toner, the polarity of the voltage applied to the brush member of the cleaning unit arranged on the most upstream side in the rotation direction of the intermediate transfer member and the state of being held on the surface of the image carrier. It is preferable that the polarity of the toner constituting the toner image is different.
Furthermore, for the same reason, when two or more cleaning units are arranged in series along the rotation direction of the intermediate transfer member, the brushes of one cleaning unit and another cleaning unit arranged adjacent to each other are arranged. The polarities of the voltages applied to the members are preferably different from each other.

[Second cleaning means]
As described above, the second cleaning unit is not particularly limited as long as it is a cleaning unit including a cleaning blade that comes into contact with the outer peripheral surface of the intermediate transfer member.
However, it is more preferable that the cleaning means used in the image forming apparatus of the second aspect of the present invention has a configuration as described below.

First, when a cleaning blade is used as the cleaning means, it is preferable to use the following cleaning blade.
The first cleaning blade is made of urethane rubber, and the rebound resilience coefficient defined by JIS K6255 (1996 version) of this urethane rubber is 20% or more at 10 ° C. and 70% or less at 40 ° C. Yes, the 300% modulus specified by JIS K6251 (2004 edition) is 2000 N / cm ² or more, and the angle-type tear strength specified by JIS K6252 (2001 edition) is 700 N / cm or more. Those are preferred.

  As a more preferable physical property of the first cleaning blade, the rebound resilience coefficient at 10 ° C. is more preferably 10% or more and 25% or less, and further preferably 15% or more and 20% or less. The rebound resilience coefficient at 40 ° C. is more preferably 40% or more and 80% or less, and further preferably 50% or more and 70% or less.

  By setting the coefficient of rebound resilience within the above-mentioned range, the temperature dependence of the resilience of the cleaning blade can be suppressed, and the rebound resilience at a low temperature range can be sufficiently secured while the cleaning blade is turned over or chipped at a high temperature range. Can be suppressed.

Also, the 300% modulus is more preferably 2000N / cm ² or more 3500 N / cm ² or less.
The tear strength is more preferably 650 N / cm or more and 850 N / cm or less, and further preferably 700 N / cm or more and 800 N / cm or less.

  By setting the 300% modulus and the tear strength within the above ranges, subtle chipping of the cleaning blade can be prevented.

Therefore, when the first cleaning blade is used as the cleaning means, even when the substantially spherical toner, which is likely to cause a cleaning failure, is used, the cleaning failure can be reliably ensured even under a condition where the environmental variation from low temperature and low humidity to high temperature and high humidity is large. And it can prevent enough. Further, even in a high-speed machine having a high process speed, it is possible to suppress slipping of the toner remaining on the outer peripheral surface of the intermediate transfer member between the intermediate transfer member and the intermediate transfer member, thereby ensuring an excellent cleaning effect.
In order to further enhance the above-described effect, the 100% permanent elongation defined by JIS K6262 (1996 version) of the cleaning blade is preferably 2.5% or less, more preferably 2.0%. It is as follows.

  The contact angle (elevation angle with respect to the tangent at the contact point) with which the first cleaning blade contacts the intermediate transfer member is preferably 10 to 45 degrees, and more preferably 20 to 30 degrees. Moreover, it is preferable to attach so that the linear pressure of a 1st cleaning blade may be 0.2-2 N / cm, More preferably, it is a case where it attaches at 0.3-1 N / cm. When the cleaning blade is attached at such a contact angle and linear pressure, the cleaning effect of the toner remaining on the outer peripheral surface of the intermediate transfer member is good.

The second cleaning blade is a combination of a cleaning brush that is rotatable in contact with the outer peripheral surface of the intermediate transfer member, and a solid lubricant supply means that supplies a solid lubricant to the outer peripheral surface of the intermediate transfer member via the cleaning brush. And preferably used. Such a cleaning apparatus is disclosed in Japanese Patent Application Laid-Open No. 2003-58009.
In this cleaning device, the cleaning brush is disposed upstream of the cleaning blade in the rotation direction of the intermediate transfer member, and further, a solid lubricant is applied to the outer peripheral surface of the intermediate transfer member via the cleaning brush. Lubricant application means is provided.

The rebound resilience coefficient defined by JIS K6255 (1996 version) of the blade material of the cleaning blade is in the range of 45 to 65% at 40 ° C., preferably 50 to 60%.
The 300% modulus specified by JIS K6251 (2004 edition) is in the range of 1000 to 2500 N / cm ² , and preferably 1500 to 2400 N / cm ² .

  The material of the second cleaning blade is preferably composed of thermosetting urethane.

The contact angle with which the second cleaning blade contacts the intermediate transfer member is in the range of 22 to 32 degrees, and preferably 23 to 30 degrees.
The second cleaning blade is attached so that the linear pressure is 0.2 to 0.5 N / cm, and preferably 0.25 to 0.45 N / cm.

The fiber applied to the cleaning brush used in combination with the second cleaning blade preferably has an electrical resistance of about 1 × 10 ⁰ to 1 × 10 ⁶ Ω, more preferably 1 × 10 ² to 1 × 10 ^5. Ω. The material of the cleaning brush fiber is preferably an acrylic fiber added with carbon, nylon fiber, polypropylene fiber, polyester fiber, or the like, more preferably acrylic fiber. The thickness of the fiber is preferably about 8 to 25 μm. Planted bristle density of the ^{fibers, 1 × 10 3 ~1 × 10} 4 present / cm ² is preferably about.

  The brush member is preferably attached to the intermediate transfer member so as to bite 1 to 3 mm, more preferably 1.2 to 2 mm. The rotation speed of the brush member is preferably 40 to 180 mm / s, more preferably 50 to 100 mm / s.

  When a cleaning device including a second cleaning blade and a cleaning brush is used, the sliding friction coefficient between the outer peripheral surface of the intermediate transfer member and the toner remaining on the surface can be reduced by the action of the solid lubricant. Can be prevented from rolling on the outer peripheral surface of the intermediate transfer member, and the cleaning performance by the cleaning blade can be improved. Further, since the adhesion between the edge of the cleaning blade and the outer peripheral surface of the intermediate transfer member is improved, a stick-slip phenomenon that promotes toner removal is likely to occur. For this reason, the cleaning performance is improved even with an intermediate (within 45 to 65%) cleaning blade having a rebound resilience coefficient of less than 70%, which is called high resilience.

  On the other hand, the rebound resilience coefficient of the cleaning blade can be suppressed to a moderate level while ensuring the cleanability, so that the 300% modulus having a negative correlation with the rebound resilience coefficient can be increased, so that sufficient mechanical strength is obtained. It can be secured. Therefore, when the friction coefficient between the intermediate transfer member and the cleaning blade increases under high temperature and high humidity, and further, the stick-slip phenomenon is suppressed under low temperature and low humidity. It is possible to suppress the occurrence of damage such as chipping of the cleaning blade, which tends to occur when the cover is covered by the adjustment.

In other words, on the premise of using solid lubricant, the cleaning blade stick slip even under low temperature and low humidity conditions by balancing the characteristics of the cleaning blade itself with the usage conditions (contacting, linear pressure). Since the movement is effectively generated, residual toner can be cleaned, and at the same time, mechanical damage such as chipping of the blade edge can be suppressed regardless of the use environment conditions.
Therefore, when the above-described cleaning device is used, a good cleaning effect can be obtained under a wide range of use conditions even when a toner having a small diameter and a substantially spherical shape that easily causes defective cleaning is used.

Examples of the solid lubricant include zinc stearate, magnesium palmitate, zinc oleate and the like as disclosed in JP-A No. 2003-58009, and those having a JIS pencil hardness of B or higher are preferable.
In addition, in the solid lubricant, porous powder such as porous glass or zeolite, or hydrophilic powder may be mixed as needed to remove deposits adhered to the surface of the intermediate transfer member. Good. The solid lubricant can be applied at a consumption amount of about 0.1 to 1.0 μg per rotation of the intermediate transfer member.

As the lubricant application means, as disclosed in Japanese Patent Application Laid-Open No. 2003-58009, for example, a solid lubricant attached to a support plate can be used so as to come into contact with the cleaning brush. However, it is not limited to this. In the lubricant applying means having the above-described configuration, the supply amount of the solid lubricant can be adjusted by the depth of biting into the cleaning brush and the contact area. In addition, when the lubricant applying means is installed substantially directly above the gravity direction of the cleaning brush, the biting depth can be adjusted by the weight of the support plate and the solid lubricant.
In addition, a flicker bar may be provided so that an appropriate amount of the toner and the solid lubricant adhering to the cleaning brush can be removed by flicking.

[Specific Configuration of Image Forming Apparatus]
Next, a specific configuration of the image forming apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing a configuration example of an image forming apparatus according to the present invention.
The image forming apparatus includes a cleaning device 10, a photosensitive drum 21 as an image carrier, an intermediate transfer belt 22 as an intermediate transfer member, a static elimination lamp 91 (light static elimination means) for neutralizing the intermediate transfer belt 22, and a transfer electrode. Bias roller 23 (secondary transfer portion), paper tray 24 for supplying recording paper as a transfer material, black developing device 25 using Bk (black) toner, yellow developing device 26 using Y (yellow) toner, M (magenta) toner Magenta developing device 27 by C, cyan developing device 28 by C (cyan) toner, peeling claw 33, belt rollers 41, 43 and 44, backup roller 42, conductive roll 45 (primary transfer portion), electrode roller 46, cleaning blade 51, recording paper (transfer material) 61, pickup roller 62, and feed roller 3 made have. The intermediate transfer belt 22 shown in FIG. 1 is a photoconductive intermediate transfer member.

  Next, the configuration of the image forming apparatus shown in FIG. 1 will be described. Around the photosensitive drum 21, a black developing unit 25, a yellow developing unit 26, a magenta developing unit 27, and a cyan developing unit 28 are arranged in this order along the arrow A direction. In addition, a conductive roll 45 is disposed on the opposite side of the photosensitive drum 21 from the side where the four color developing devices are disposed so that the intermediate transfer belt 22 is sandwiched between the conductive roll 45 and the photosensitive drum 21. ing.

The intermediate transfer belt 22 is stretched by a conductive roll 45, a belt roller 41, a belt roller 43, a backup roller 42, and a belt roller 44 that are sequentially arranged in the direction of arrow B in contact with the inner peripheral surface thereof. The cleaning device 10 is disposed on the opposite side of the belt roller 44 with the belt 22 in between. Further, the peeling claw 33 is disposed so as to contact the outer peripheral surface of the portion of the intermediate transfer belt 22 stretched by the backup roller 42 and the belt roller 44.
In addition, on the outer peripheral surface side of the intermediate transfer belt 22 between the belt roller 44 and the backup roller 42, a static elimination lamp 91 is provided downstream of the peeling claw 33 in the rotation direction of the intermediate transfer belt 22 (in the direction of arrow B in the figure). In addition, a conductive member 90 for static elimination that is grounded (not shown) is installed so as to be in contact with the inner peripheral portion thereof.

  The backup roller 42 is in pressure contact with the bias roller 23 via the intermediate transfer belt 22, and the recording paper 61 can be inserted between the backup roller 42 (the intermediate transfer belt 22 pressed against) and the bias roller 23. It is. A cleaning blade 51 is provided around the bias roller 23 so as to be in contact with the surface. In addition, an electrode roller 46 is disposed in contact with the backup roller 42 on the substantially opposite side of the backup roller 42 on which the bias roller 23 is disposed.

  In a direction in which the recording paper 61 passes between the backup roller 42 and the bias roller 23, a pair of mutually contacting feed rollers 63 is disposed, and the recording paper 61 can be inserted between the two feed rollers 63. . Further, on the opposite side of the pair of feed rollers 63 from the side where the backup roller 42 and the bias roller 23 are provided, a paper tray 24 storing the recording paper 61, and a pair of feed rollers for feeding the recording paper 61 from the paper tray 24. A pickup roller 62 is disposed to be supplied to the contact portion 63.

The cleaning apparatus 10 shown in FIG. 1 is the first cleaning means provided with a conductive brush (brush member), and details thereof are shown in FIG. FIG. 2 is a schematic diagram showing a configuration example of the cleaning device used in the image forming apparatus according to the first aspect of the invention, and shows a state where the cleaning device is arranged in the image forming apparatus shown in FIG.
The cleaning device 10 includes a housing 14 having an opening on the intermediate transfer belt 22 side, and a conductive brush 11a, a conductive roll 12a, and a scraper (blade) 13a disposed in the housing 14. And a second cleaning unit comprising a conductive brush 11b, a conductive roll 12b, and a scraper (blade) 13b. In the drawing, the configuration other than the main part such as an auger for removing residual toner to the outside of the cleaning device is omitted.

  Specifically, the first cleaning unit includes a conductive brush 11a that contacts the outer peripheral surface of the intermediate transfer belt 22, a conductive roll 12a that contacts the conductive brush 11a, and one end that is the inner wall of the housing 14. The other end portion is composed of a scraper 13a that comes into contact with the conductive roll 12a. The conductive brush 11a and the conductive roll 12a are connected to a power source (not shown) so that a voltage of a predetermined polarity can be applied. It is connected. The second cleaning unit also has substantially the same configuration as the first cleaning unit except that the arrangement relationship of each member is slightly different. It should be noted that the arrangement relationship with respect to the rotation direction of the intermediate transfer belt 22 is that the first cleaning unit is upstream of the intermediate transfer belt 22 in the rotation direction (static discharge lamp 91 side), and the second cleaning unit is the rotation of the intermediate transfer belt 22. Direction downstream.

  Next, image formation using the image forming apparatus shown in FIG. 1 will be described. First, the photosensitive drum 21 rotates in the direction of arrow A, and its surface is uniformly charged by a charging device (not shown). An electrostatic latent image of the first color (for example, Bk) is formed on the charged photosensitive drum 21 by image writing means such as a laser writing device. The electrostatic latent image is developed with toner by the black developing device 25 to form a visualized toner image T. The toner image T reaches the primary transfer portion where the conductive roll 45 is disposed by the rotation of the photosensitive drum 21, and an electric field having a reverse polarity is applied to the toner image T from the conductive roll 45, whereby the toner image T Is primarily transferred by the rotation of the intermediate transfer belt 22 in the direction of arrow B while being electrostatically attracted to the intermediate transfer belt 22.

Thereafter, similarly, a second color toner image, a third color toner image, and a fourth color toner image are sequentially formed and superimposed on the intermediate transfer belt 22 to form a multiple toner image.
The multiple toner image transferred to the intermediate transfer belt 22 reaches the secondary transfer portion where the bias roller 23 is installed by the rotation of the intermediate transfer belt 22. The secondary transfer unit includes a bias roller 23 installed on the surface side where the toner image of the intermediate transfer belt 22 is carried, a backup roller 42 disposed so as to face the bias roller 23 from the back side of the intermediate transfer belt 22, and The electrode roller 46 is configured to press and rotate against the backup roller 42.

  The recording paper 61 is picked up one by one from the recording paper bundle stored in the paper tray 24 by the pickup roller 62, and is fed at a predetermined timing between the intermediate transfer belt 22 and the bias roller 23 of the secondary transfer portion by the feed roller 63. It is sent by. A toner image carried on the intermediate transfer belt 22 is transferred to the fed recording paper 61 by pressure contact conveyance by the bias roller 23 and the backup roller 42 and rotation of the intermediate transfer belt 22.

The recording paper 61 onto which the toner image has been transferred is peeled from the intermediate transfer belt 22 by operating the peeling claw 33 in the retracted position until the primary transfer of the final toner image is completed, and is conveyed to a fixing device (not shown). The toner image is fixed by heat treatment to be a permanent image.
The bias roller 23 is attached so that a cleaning blade 51 made of polyurethane or the like is always in contact therewith, and foreign matters such as toner particles and paper dust adhered by transfer are removed.

  In the case of transfer of a single color image, the primary transferred toner image T is immediately secondarily transferred and conveyed to the fixing device. In the case of transfer of a multicolor image by superimposing a plurality of colors, the toner image of each color is transferred to the primary transfer unit. Therefore, the rotation of the intermediate transfer belt 22 and the photosensitive drum 21 is synchronized so that the toner images of the respective colors do not shift so as to match exactly. In the secondary transfer portion, an output pressure (transfer voltage) having the same polarity as the polarity of the toner image is applied to an electrode roller 46 that is in pressure contact with a backup roller 42 that is disposed opposite to the bias roller 23 via the intermediate transfer belt 22. Then, the toner image is transferred to the recording paper 61 by electrostatic repulsion.

  Further, after the transfer of the multiple toner image onto the recording paper 61 is completed and the recording paper 61 is peeled off by the peeling claw 33, the outer peripheral surface of the intermediate transfer belt 22 is irradiated with light from the static elimination lamp 91. By this light irradiation, the outer peripheral surface of the intermediate transfer belt 22 develops electrical conductivity and is neutralized. Subsequently, the outer peripheral surface of the intermediate transfer belt 22 that has been neutralized is cleaned by the cleaning device 10 provided on the downstream side of the neutralization lamp 91 in the rotational direction of the intermediate transfer belt 22.

During cleaning, since the outer peripheral surface of the intermediate transfer belt 22 is neutralized, the electrostatic action between the outer peripheral surface of the intermediate transfer belt 22 and the residual toner existing on this surface is weakened, and the cleaning effect is enhanced. it can.
Further, the polarity of the voltage applied to the conductive brush 11a of the first cleaning unit is different from the polarity of the voltage applied to the conductive brush 11b of the second cleaning unit, and is applied to the conductive brush 11a. By making the polarity of the voltage to be different from the polarity of the toner constituting the toner image held on the surface of the photosensitive drum 21, the cleaning effect can be further enhanced.
That is, most of the residual toner existing on the outer peripheral surface of the intermediate transfer belt 22 is removed by the first cleaning unit, and the photosensitive member of the residual toner existing on the outer peripheral surface of the intermediate transfer belt 22 is removed by the first cleaning unit. It is possible to remove the residual toner that is slightly present and charged to a polarity opposite to that when the toner image is formed on the surface of the drum 21.

Hereinafter, the transfer mechanism using the intermediate transfer belt 22 which is an intermediate transfer member used in the present invention and the charge eliminating mechanism of the intermediate transfer belt 22 will be described again in more detail with reference to FIG. A specific configuration of the transfer belt 22 will be described later).
The intermediate transfer belt 22 shown in FIG. 1 includes a primary transfer area Q3 that comes into contact with the surface of the photosensitive drum 21 of the image forming apparatus, a secondary transfer area Q4 that comes into contact with the recording paper 61, and a static elimination area Q5 due to the static elimination lamp 91. Are rotated in the direction of arrow B so as to pass sequentially. Here, the intermediate transfer belt 22 when passing through the primary transfer region Q3 and the secondary transfer region Q4 is not irradiated with light but is in a dielectric state. When the intermediate transfer belt 22 passes through the primary transfer region Q3, the toner image on the surface of the photosensitive drum 21 is primarily transferred, and the primary transferred toner image is transferred to the recording paper 61 when passing through the secondary transfer region Q4. Next transferred.

  As described above, the intermediate transfer belt 22 that is an intermediate transfer member used in the present invention is a dielectric and has a high volume resistivity when the surface layer is not irradiated with light. Therefore, the primary transfer and the secondary transfer are performed. In some cases, transfer can be performed in a dielectric (insulator) state. At this time, since the movement of charges along the surface of the surface layer (photoconductive layer) of the intermediate transfer belt 22 is small, good transfer with less scattering of the toner image is performed in the primary transfer region Q3 and the secondary transfer region Q4. It can be carried out.

In the image forming apparatus of the present invention, the toner does not matter whether the charging characteristic is negative or positive. However, for the sake of convenience, the description will be made using negative toner.
In the case of negatively charged toner, primary transfer is performed by applying a positive voltage to the conductive roll 45 (primary transfer means). As a result, the intermediate transfer belt 22 after the primary transfer accumulates positive charges due to the conductive roll 45 on the back side, and accumulates negative charges due to toner and counter charge on the front side. In order to obtain a color image, the primary transfer voltage is sequentially increased after the second color, and a plurality of color toner images may be formed on the intermediate transfer belt 22.

Subsequently, during the secondary transfer, when the toner image is transferred to the recording paper 61, non-uniform positive charges corresponding to the secondary transfer image are supplied to the front surface side of the intermediate transfer belt 22, and to the back surface side. Is supplied with a negative charge. The surface potential of the intermediate transfer belt 22 after the secondary transfer is − (minus) when the secondary transfer voltage is lower than the primary transfer voltage, and when the secondary transfer voltage is higher than the primary transfer voltage, + (Plus).
Here, when the primary transfer process of the next image is performed in a state where the surface potential of the intermediate transfer belt 22 remains, the image is blurred, scattered, and thickened due to the occurrence of primary transfer unevenness due to the non-uniformity of the accumulated charge. Etc. will occur. Further, if there is no neutralization mechanism on the surface of the intermediate transfer belt 22 and negative charges are accumulated even after the secondary transfer, the charges are accumulated every time the primary transfer and the secondary transfer are repeated. The surface potential of the image becomes excessively high-(minus) value (the back surface side is excessively high positive (positive) surface potential). Therefore, the required primary transfer voltage in the next image is also very high. End up.
For this reason, after the secondary transfer, it is necessary to keep the charge accumulated on the intermediate transfer belt 22 uniformly below a certain level. Here, the certain level is a level determined according to the surface potential of the photosensitive drum 21, the toner charge amount, the form of the pre-transfer area, and the like.

  In the present invention, since an intermediate transfer member having a photoconductive layer as a surface layer is used as the intermediate transfer belt 22, the surface charge of the intermediate transfer belt 22 is irradiated with light by a static elimination lamp 91 after the secondary transfer. The accumulated charge can be easily removed by light. This is because the free carriers generated by the photoconductive substance in the intermediate transfer belt 22 absorbing light neutralize the opposing charges existing on the surface. The neutralizing lamp 91 only needs to have a light source having a wavelength in the photosensitivity region of the photoconductive substance added to the photoconductive layer, and its intensity and photo neutralization position may be determined as needed. As the static elimination lamp 91, for example, a red LED can be used.

  Further, the charge accumulated in the intermediate transfer belt 22 is subjected to light neutralization by the neutralization lamp 91 and then further transferred to the intermediate transfer by the grounded conductive member 90 for neutralization which is in contact with the inner peripheral portion of the intermediate transfer belt 22. It is preferable that the belt 22 is discharged out of the belt 22. Therefore, with respect to the rotation direction of the intermediate transfer belt 22, the charge removal conductive member 90 is provided at the same position as the charge removal lamp 91 as shown in FIG. 1 or downstream of the rotation direction of the intermediate transfer belt 22. It is preferable. Further, as shown in FIG. 1, the charge removal conductive member 90 can be disposed not only on the inner peripheral side of the intermediate transfer belt 22 but also on the outer peripheral surface side. Ejection (removal) is performed.

As the conductive member 90 for static elimination, an elastic roll (for example, an epichlorohydrin rubber roll with carbon black dispersion) in which a conductive agent whose volume resistivity is adjusted to 1 × 10 ⁵ to 1 × 10 ¹⁰ Ω is used is used. Can do. As described above, the conductive member 90 for charge removal may be in a roll shape, a blade shape, or a brush shape.

The neutralizing conductive member 90 can be disposed on either the inner peripheral surface side or the outer peripheral surface side of the intermediate transfer belt 22. When the conductive member 90 is disposed on the inner peripheral surface side, it is always brought into contact with the intermediate transfer belt 22. However, when the color toner image is arranged on the outer peripheral surface side, it is arranged at a position away from the intermediate transfer belt 22 until the secondary transfer is completed at the time of the multiple transfer of the color toner image. It is necessary to configure so as to contact the intermediate transfer belt 22 when performing static elimination.
In that case, a moving mechanism for moving the neutralizing conductive member 90 between a position in contact with the intermediate transfer belt 22 and a position away from the intermediate transfer belt 22 is required. Therefore, when the electrically conductive member 90 for static elimination is arranged so as to be always in contact with the inner peripheral surface of the intermediate transfer belt 22, the moving mechanism is not required, the configuration is simplified, and the cost is reduced. .

From the above, the image forming apparatus of the present invention having the above-described configuration uses the intermediate transfer member used in the present invention as the intermediate transfer belt 22, and can further easily remove the charge on the intermediate transfer belt 22. Since the discharge lamp 91 (light discharge means) is also provided, image quality defects due to toner scattering are remarkably reduced, and a high-quality transfer image quality can be stably obtained.
Furthermore, since the cleaning unit (cleaning means) 10 includes a cleaning unit including conductive brushes (brush members) 11a and 11b that are used in a state where a voltage is applied during cleaning, the cleaning effect is extremely high, and cleaning is performed. Even when a small-diameter or substantially spherical toner that tends to cause a defect is used, it is possible to suppress deterioration in image quality due to a cleaning defect.

Next, a tandem type color image forming apparatus including an intermediate transfer belt made of an intermediate transfer member used in the present invention, and a plurality of image carriers having developing units for respective colors arranged in series on the intermediate transfer belt. Will be described with reference to the drawings.
FIG. 3 is a schematic diagram showing another example of the image forming apparatus of the present invention. The image forming apparatus shown in FIG. 3 includes four toner cartridges 71, a pair of fixing rolls 72, a backup roll 73, a tension roll 74, a secondary transfer roll 75, a paper path 76, a paper tray 77, a laser generator 78, 4 Two photoreceptors 79, four primary transfer rolls 80, a drive roll 81, a cleaning device 10, four charging rolls 83, a photoreceptor cleaner 84, a developing device 85, an intermediate transfer belt 86, and a static elimination lamp that neutralizes the intermediate transfer belt 86. 91 (light static elimination means), a static elimination conductive member 90, and the like are included as main constituent members. In the image forming apparatus shown in FIG. 3, the intermediate transfer member used in the present invention is used as the intermediate transfer belt 86.

  Next, the configuration of the image forming apparatus shown in FIG. 3 will be sequentially described. First, around the photoconductor 79, a primary transfer roll 80 and a photoconductor cleaner 84 arranged counterclockwise via a charging roll 83, a developing device 85, and an intermediate transfer belt 86 are arranged. The member forms a developing unit corresponding to one color. Each developing unit is provided with a toner cartridge 71 for replenishing the developer in the developing unit 85. The photosensitive member 79 of each developing unit is exposed to a photosensitive member between the charging roll 83 and the developing unit 85. A laser generator 78 capable of irradiating the surface of the body 79 with laser light corresponding to image information is provided.

Four developing units corresponding to four colors (for example, cyan, magenta, yellow, and black) are arranged in series in a substantially horizontal direction in the image forming apparatus. An intermediate transfer belt 86 is provided so as to pass through the nip portion with the transfer roll 80. The intermediate transfer belt 86 is stretched by a backup roll 73, a tension roll 74, and a drive roll 81 provided in the counterclockwise direction in the following order on the inner peripheral side thereof. The four primary transfer rolls are located between the backup roll 73 and the tension roll 74. A cleaning device 10 for cleaning the outer peripheral surface of the intermediate transfer belt 86 is provided on the opposite side of the drive roll 81 with the intermediate transfer belt 86 in contact with the drive roll 81.
The cleaning device 10 is not particularly limited as long as it uses a cleaning unit including a conductive brush (brush member) that is used in a state where a voltage is applied during cleaning. For example, the cleaning device 10 illustrated in FIG. An apparatus having the same configuration as that of the cleaning apparatus 10 can be used.

  A toner image formed on the outer peripheral surface of the intermediate transfer belt 86 on the surface of the recording paper conveyed from the paper tray 77 via the paper path 76 to the opposite side of the backup roll 73 via the intermediate transfer belt 86. A secondary transfer roll 75 for transferring the image is provided so as to be in pressure contact with the backup roll 73. A neutralizing lamp 91 is installed on the outer peripheral surface side of the intermediate transfer belt 86 between the backup roll 73 and the drive roll 81, and is grounded (not shown) so as to contact the inner peripheral surface. 90 is installed.

  Further, a paper tray 77 for stocking recording paper is provided at the bottom of the image forming apparatus, and a backup roll 73 and a secondary transfer roll 75 that constitute a secondary transfer unit from the paper tray 77 via a paper path 76 are provided. It can supply so that it may pass a press-contact part. The recording paper that has passed through the pressure contact portion can be further transported by a transport means (not shown) so as to pass through the pressure contact portions of the pair of fixing rolls 72, and can finally be discharged out of the image forming apparatus.

  Next, an image forming method using the image forming apparatus of FIG. 3 will be described. The toner image is formed for each developing unit. After uniformly charging the surface of the photoreceptor 79 rotating counterclockwise by the charging roll 83, the photoreceptor 79 charged by the laser generator 78 (exposure apparatus) is charged. A latent image is formed on the surface, and then the latent image is developed with a developer supplied from a developing device 85 to form a toner image, which is conveyed to a pressure contact portion between the primary transfer roll 80 and the photoreceptor 79. The transferred toner image is transferred to the outer peripheral surface of the intermediate transfer belt 86 rotating in the direction of arrow C. The photosensitive member 79 after the toner image has been transferred is cleaned of toner, dust and the like adhering to the surface thereof by a photosensitive member cleaner 84 to prepare for the formation of the next toner image.

  The toner images developed for each color development unit are sequentially superimposed on the outer peripheral surface of the intermediate transfer belt 86 so as to correspond to the image information, and are conveyed to the secondary transfer unit by the secondary transfer roll 75. The image is transferred from the sheet tray 77 to the surface of the recording sheet conveyed via the sheet path 76. The recording paper on which the toner image has been transferred is further fixed by being heated by pressure when passing through the pressure contact portion of a pair of fixing rolls 72 constituting the fixing portion, and after the image is formed on the surface of the recording medium. Then, it is discharged out of the image forming apparatus.

  The intermediate transfer belt 86 that has passed through the secondary transfer portion further proceeds in the direction of arrow C, and charges accumulated by the charge removal lamp 91 and the charge removal conductive member 90 are discharged. Thereafter, after the outer peripheral surface is further cleaned by the cleaning device 10, it is prepared for the transfer of the next toner image.

The charge accumulated on the intermediate transfer belt 86 is transferred to the outside of the intermediate transfer belt 86 by the charge removal conductive member 90 in addition to the light charge removal by the charge removal lamp 91 as in the charge removal mechanism of the intermediate transfer belt 22 described above. It is preferable that the charge is removed by discharging the electric charge. The static elimination lamp 91 and the static elimination conductive member 90 used here are the same as the static elimination lamp 91 and the static elimination conductive member 90 in the image forming apparatus shown in FIG.
The relationship between the installation positions of the static elimination lamp 91 and the static elimination conductive member 90 is the same as the relation between the static elimination lamp 91 and the static elimination conductive member 90 in the image forming apparatus shown in FIG.
Further, in the image forming apparatus shown in FIG. 3, for example, a red LED can be used as the charge eliminating lamp 91. Moreover, the electrically conductive member 90 for charge removal can be disposed on either the back surface side or the front surface side of the intermediate transfer belt 86. Here, the electrically conductive member 90 for charge removal has a volume resistivity of 1 × 10 ⁵ to 1 ×. An elastic roll (for example, an epichlorohydrin rubber roll with carbon black dispersion) can be used by dispersing a conductive agent adjusted to 10 ¹⁰ Ω.

From the above, the tandem image forming apparatus having the configuration also uses the intermediate transfer member used in the present invention as the intermediate transfer belt 86, and further, the charge removal that can easily remove the charge of the intermediate transfer belt 86. Since the lamp 91 (light static elimination means) is also used, image quality defects due to toner scattering are remarkably reduced, and high-quality transfer image quality can be stably obtained.
Further, since the cleaning unit (cleaning means) 10 includes a cleaning unit including a conductive brush (brush member) that is used in a state where a voltage is applied during cleaning, the cleaning effect is extremely high, resulting in poor cleaning. Even when a small-diameter or substantially spherical toner that is easy to use is used, it is possible to suppress deterioration in image quality due to poor cleaning.

  The cleaning device 10 in the image forming apparatus shown in FIGS. 1 and 3 may be replaced with the cleaning devices 15 and 15 ′ shown in FIGS. 4 (A) and 4 (B).

FIGS. 4A and 4B are schematic schematic views showing one configuration example of the cleaning device used for the second cleaning means.
The cleaning device 15 shown in FIG. 4A includes a housing 19 having an opening on the intermediate transfer belt 22 side, and the rotation direction of the intermediate transfer belt 22 (in the direction of arrow B in FIG. 4, the arrow shown in FIG. In the B direction (synonymous with the arrow C shown in FIG. 3), the cleaning blade 16 is mounted on the downstream side of the opening of the housing 19 and abuts the outer peripheral surface of the intermediate transfer belt 22. A rotatable cleaning brush 17 that contacts the outer peripheral surface of the belt 22 and a solid lubricant supply means 18 that supplies a solid lubricant to the cleaning brush 17 are configured. Here, the solid lubricant supply means 18 is fixed so that a solid lubricant supported by a support (not shown) bites into the cleaning brush 17 at a certain depth.
In the drawing, the configuration other than the main part such as an auger for removing residual toner to the outside of the cleaning device is omitted.

During cleaning, since the outer peripheral surface of the intermediate transfer belt 22 is neutralized, the electrostatic action between the outer peripheral surface of the intermediate transfer belt 22 and the residual toner existing on this surface is weakened, and the cleaning effect is enhanced. it can.
Further, due to the action of the solid lubricant supplied to the outer peripheral surface of the intermediate transfer belt 22 from the solid lubricant supply means 18 via the cleaning brush 17, the adhesion between the cleaning blade 16 and the outer peripheral surface of the intermediate transfer belt 22 is increased. Even in a low-temperature and low-humidity environment, the stick-slip phenomenon can be effectively generated and good cleaning properties can be obtained. Further, since the solid lubricant supplied to the outer peripheral surface of the intermediate transfer belt 22 is recovered by being scraped off by the cleaning blade 16, the primary transfer is not adversely affected. In the configuration shown in FIG. 4A, the first cleaning blade or the second cleaning blade is preferably used as the cleaning blade 16, and more preferably, the second cleaning blade is used. is there.

  The cleaning device 15 ′ shown in FIG. 4B is the same as the cleaning device 15 shown in FIG. 4A except that the solid lubricant supply means 18 is omitted, and thus the description thereof is omitted. In the case of the cleaning device 15 ′ shown in FIG. 4B, it is preferable to use the first cleaning blade or the second cleaning blade as the cleaning blade 16.

[Toner (and developer)]
The toner used in the image forming apparatus of the present invention can be used without particular limitation as long as it is a known toner, such as a toner using a dry method such as a pulverization method or a toner using a wet method such as an emulsion polymerization aggregation method. However, it is preferable to use a so-called spherical toner having a high sphericity.

By using a spherical toner as the toner and further combining with the intermediate transfer member used in the present invention as described above, the transfer efficiency can be further improved, so there is no image quality defect (holo character, blur, color registration). High quality transfer image quality can be obtained.
In addition, if a toner having a small volume particle size is used, a higher-definition image can be formed.
Furthermore, it is possible to suppress deterioration in image quality due to such a cleaning defect that is a disadvantage of the toner.

  On the other hand, a toner having a small diameter or high sphericity tends to cause poor cleaning as compared with a toner having a low body diameter or low sphericity. However, in the image forming apparatus of the present invention, since the intermediate transfer member used in the present invention as described above and the cleaning unit are used in combination, transfer can be performed with high transfer efficiency while suppressing occurrence of toner scattering. In addition, the occurrence of cleaning defects can be suppressed. For this reason, excellent image quality can be obtained even when spherical toner having a high sphericity defined by a shape factor described later or a toner having a small volume average particle diameter is used.

The spherical toner means that its shape factor (SF) is 140 to 100. The shape factor is preferably 130 to 100 or less, and more preferably 120 to 100 or less. When this average shape factor (SF) is larger than 140, the transfer efficiency is lowered, and the deterioration of the image quality of the print sample can be visually confirmed.
Here, the shape factor (SF) is a factor defined by the following equation (1).
Formula (1) SF = [(maximum length of toner particles) ² × π × 100] / [projection area of toner particles × 4]

  The maximum length of toner particles and the projected area of the toner particles are determined by analyzing the optical microscope image of the toner dispersed on the slide glass using a Luzex image analyzer (manufactured by Nireco Corporation, FT) through a video camera. It can be measured by taking in the apparatus and determining the maximum length and projected area of 50 or more toners.

  The toner used in the present invention contains at least a binder resin and a colorant. The volume average particle size of the toner is preferably in the range of 2 to 12 μm, more preferably in the range of 2.5 to 9 μm, and still more preferably in the range of 3 to 6 μm.

  Binder resins include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate, and methyl acrylate. , Α-methylene aliphatic monocarboxylic esters such as ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, vinyl Examples thereof include homopolymers and copolymers of vinyl ethers such as methyl ether, vinyl ethyl ether, and vinyl butyl ether, and vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone.

  Typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. Examples thereof include coalescence, polyethylene, and polypropylene. Furthermore, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax, and the like can be given.

  Coloring agents include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, and lamp black. Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is a typical example.

  The toner may be internally added or externally added with a known additive such as a charge control agent, a release agent, or other inorganic fine particles. Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  Known charge control agents can be used, but azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. When the toner is manufactured by a wet manufacturing method, it is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination.

As other inorganic fine particles, small-sized inorganic fine particles having an average primary particle diameter of 40 nm or less are used for the purpose of powder flowability, charge control, etc., and if necessary, larger diameters are used to reduce adhesion. These inorganic or organic fine particles may be used in combination. As these other inorganic fine particles, known ones can be used. Examples thereof include silica, alumina, titania, metatitanic acid, zinc oxide, zirconia, magnesia, calcium carbonate, magnesium carbonate, calcium phosphate, cerium oxide, and strontium titanate.
In addition, the surface treatment of the small-diameter inorganic fine particles is effective because the dispersibility becomes high and the effect of increasing the powder fluidity increases.

The toner used in the present invention is not particularly limited by the production method, and can be obtained by a known method.
Specifically, for example, in addition to a binder resin and a colorant, a kneading and pulverizing method in which a release agent, a charge control agent, and the like are kneaded, pulverized, and classified as necessary, and particles obtained by the kneading and pulverizing method are machined. The shape is changed by mechanical impact force or thermal energy, the polymerizable monomer constituting the binder resin is emulsion-polymerized, and the formed dispersion and the dispersion containing the colorant are separated as necessary. Emulsion polymerization aggregation method to obtain a spherical toner by mixing with a dispersion liquid such as a mold agent and a charge control agent, and agglomeration, heat fusion, a polymerizable monomer to obtain a binder resin, a colorant, and the like Depending on the suspension polymerization method in which a solution of a release agent, a charge control agent, etc. is suspended in an aqueous solvent for polymerization, a binder resin and a colorant and, if necessary, a solution of a release agent, a charge control agent, etc. in an aqueous system Examples thereof include a dissolution suspension method in which particles are suspended in a solvent and granulated.

The toner obtained by the above method may be used as a core particle, and a toner having a core-shell structure produced through a process of heat fusion after further binding resin fine particles are attached to the core particle may be used.
Further, when an external additive is added to the toner, it can be produced by mixing the toner and the external additive with a Henschel mixer or a V blender. In addition, when the spherical toner is manufactured by a wet method, it can be externally added by a wet method.

  As the external additive, various known additives can be used, and examples thereof include silica, alumina, titanium oxide (titanium oxide, metatitanic acid, etc.), calcium carbonate, magnesium carbonate, calcium phosphate, carbon black and the like. it can. The average primary particle size is preferably in the range of 1 to 80 nm. The kind and particle size of the additive can be appropriately selected according to the purpose.

The toner can be used as either a one-component developer or a two-component developer.
When the toner is used as a two-component developer mixed with a carrier, a known carrier can be used. For example, a resin-coated carrier having a resin coating layer on the surface of the core material can be exemplified. Further, a resin-dispersed carrier in which magnetic powder or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples include acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins, urea resins, urethane resins, melamine resins, etc. It is not limited.

  In general, the carrier preferably has an appropriate electric resistance value, and it is preferable to disperse the conductive fine powder in the resin for adjusting the resistance. Examples of the conductive fine powder include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black. However, it is not limited to these.

  Examples of the carrier core material include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, a magnetic material is used. Preferably there is. The volume average particle size of the carrier core material is preferably in the range of 10 to 100 μm, and more preferably in the range of 25 to 50 μm.

  In order to coat the surface of the core material of the carrier with a resin, a method of coating the coating resin and, if necessary, various additives with a solution for forming a coating layer dissolved in an appropriate solvent is employed. The solvent is not particularly limited and may be appropriately selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include a dipping method in which the powder of the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the surface of the carrier core material, and a carrier core material. Examples thereof include a fluidized bed method in which a coating layer forming solution is sprayed in a state of being suspended by flowing air, and a kneader coater method in which a carrier core material and a coating layer forming solution are mixed in a kneader coater to remove the solvent.

  When toner is used as a two-component developer, it can be obtained by mixing the toner described above and a carrier. The mixing ratio (mass ratio) of the toner and the carrier in the developer is preferably in the range of toner: carrier = 1: 99 to 20:80, preferably in the range of 3:97 to 12:88. It is more preferable.

Hereinafter, the present invention will be described in more detail with reference to examples.
<Image forming apparatus and image forming conditions>
For evaluation of the example, a DocuCenter Color 400CP manufactured by Fuji Xerox Co., Ltd. having substantially the same configuration as that of the image forming apparatus shown in FIG. 1 was used.
However, with respect to the intermediate transfer belt 22 and the cleaning device 10, intermediate transfer belts A1 to A5, B1 to B4, which will be described later, and cleaning devices A1 to A2, B1 to B2, and C1 are combined for each example / comparative example. used.

In addition, a static elimination lamp 91 and a static elimination conductive member 90 were also mounted on the Docu Color 1255CP used for evaluation as shown in FIG. Here, a red LED (wavelength 780 nm, manufactured by Akizuki Denshi Co., Ltd.) was used as the static elimination lamp 91. Further, as the charge removing conductive member 90, an epichlorohydrin rubber roll dispersed with carbon black in which a conductive agent having a volume resistance adjusted to 10 ⁶ Ω was dispersed was used.

Using this image forming apparatus, transfer image quality (blur, holo-character) and cleaning performance by secondary transfer were evaluated. The recording paper 61 used here is Fuji Xerox Office Supply Co., Ltd. full color copier paper J paper.
The print sample is configured as an image pattern, and the first sheet is composed of a solid color of 2 cm square of yellow, magenta, cyan, and black, a secondary color, and a tertiary color, and a line image.

  In addition, the test was performed at 30,000 sheets alternately in both the low temperature and low humidity environment (10 ° C, 15%) and the high temperature and high humidity environment (28 ° C, 85%) (low temperature and low humidity environment → high temperature and high humidity environment → low temperature and low humidity). Environment → high temperature and high humidity environment) A total of 120,000 sheets were printed and the process speed was set to 220 mm / s. The toner image (toner) formed and held on the image carrier is negatively charged.

<Toner (Developer)>
The following toner A1 and toner A2 were used as toners of the respective colors.
Toner A1: A spherical toner having a shape factor (SF) of 125 and a volume average particle diameter of 5.5 μm.
Toner A2: A potato-shaped toner having a shape factor (SF) of 135 and a volume average particle diameter of 6.5 μm.

Further, an external additive was added to toner A1 and toner A2 as follows, and then mixed with a carrier to obtain a developer.
First, 1.6 parts by mass of hydrophobic silica (manufactured by Cabot, TS720) was added to 50 parts by mass of the toner, and mixed with a sample mill to obtain an externally added toner. Subsequently, using the ferrite carrier having an average particle diameter of 50 μm coated with 1% by mass of polymethyl methacrylate (manufactured by Soken Chemical Co., Ltd .: weight average molecular weight: 60000), the above externally added toner is adjusted so that the toner concentration becomes 5% by mass. The two were stirred and mixed for 5 minutes by a ball mill to prepare a yellow developer having a release agent blending amount of 10% by mass and a toner volume average particle diameter of 3.5 μm.

The volume average particle diameter of the toner is a value obtained by using a Coulter Multisizer II (manufactured by Beckman-Coulter) measuring device, and is a volume with respect to a particle size range (channel) divided based on the particle size distribution. The cumulative distribution was drawn from the small particle diameter side, and the particle diameter at 50% accumulation was determined as the volume average particle diameter.
The toner shape factor SF was determined as follows. First, an optical microscope image of the toner dispersed on the slide glass is taken into a Luzex image analyzer through a video camera, and the peripheral length (ML) and the projection area (A) of 50 or more toners are measured. From 1), the toner shape factor SF was determined.

<Preparation of Intermediate Transfer Belt A1>
[Preparation of belt-shaped substrate]
(Preparation of polyamic acid solution (A))
N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-diaminodiphenyl ether (DDE) (manufactured by Ube Industries) To Euvarnish S (solid content: 18% by mass), 100 parts by mass of the solid content of the raw material capable of forming the polyimide resin in this solution, dry oxidized carbon black (SPECIAL BLACK4 (manufactured by Degussa, pH 3.0, volatile content: 14.0%)) is added to 23 parts by mass, using a collision type disperser (Geanus PY made by Genus), at a pressure of 200 MPa, a minimum area of 1.4 mm ² is divided into two parts It was made to collide afterwards, and the passage which divided into 2 again was passed 5 times, it mixed, and the polyamic-acid solution (A) containing carbon black for base materials was obtained.

(Formation of base material)
The polyamic acid solution (A) containing carbon black is applied to the inner surface of the cylindrical mold so that the thickness of the coating film becomes 0.5 mm via a dispenser, and the mold is rotated at 1500 rpm for 15 minutes to obtain a uniform thickness. After forming the coating film having a temperature of 60 ° C from the outside of the mold for 30 minutes while rotating the mold at 250 rpm, the coating film was heated to 150 ° C for 60 minutes and cooled to room temperature. Formed.
Thereafter, the film formed on the inner surface of the mold is peeled off, and this film is coated so as to cover the outer periphery of the metal core, and the temperature is increased to 400 ° C. at a rate of 2 ° C./min. For 30 minutes to remove the solvent and dehydrated ring-closing water remaining in the film and complete the imide conversion reaction. Thereafter, after cooling the metal core to room temperature, the polyimide film formed on the surface of the metal core was peeled off to obtain an endless belt-like base material having a thickness of 0.08 mm.
The obtained base material had a Young's modulus of 3,800 Mpa, a volume resistivity of 1 × 10 ^9.5 Ωcm, and a surface resistivity of 1 × 10 ¹² Ω / □.

The surface resistivity and volume resistivity were measured as follows.
(Surface resistivity)
As described above, the surface resistivity was measured using a circular electrode (High Probe IP HR probe manufactured by Dia Instruments Co., Ltd.) in a 22 ° C./55% RH environment. A voltage of 100 (V) was applied between the cylindrical electrode portion C ′ and the ring-shaped electrode portion D ′ in the voltage application electrode A ′, and the current value after 10 seconds was obtained.
(Volume resistivity)
As described above, the volume resistivity is measured by using the circular electrode (High Probe IP HR probe manufactured by Dia Instruments Co., Ltd.) and the first voltage in a 22 ° C./55% RH environment. A voltage of 100 (V) was applied between the cylindrical electrode portion C ′ and the second voltage application electrode B ′ in the application electrode A ′, and the current value after 10 seconds was obtained.

[Formation of undercoat layer]
Zinc oxide (MZ300: manufactured by Teika Co., Ltd .: specific surface area value 30 m ² / g) was heated and dried at 150 ° C. for 5 hours, and then 100 parts by mass of zinc oxide was stirred and mixed with 500 parts by mass of toluene to obtain a silane coupling agent (KBM403: 5 parts by mass) (manufactured by Shin-Etsu Chemical Co., Ltd.) was added and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 150 ° C. for 2 hours.
60 parts by mass of the zinc oxide subjected to the surface treatment, 15 parts by mass of a curing agent blocked isocyanate (Sumijoule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) and 15 parts by mass of a butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) A solution obtained by dissolving 38 parts by mass of a solution dissolved in 85 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone was dispersed using a 1 mmφ glass bead in a sand mill for 2 hours.
Dioctyltin dilaurate: 0.005 parts by mass and silicone oil SH29PA (manufactured by Toray Dow Corning Silicone): 0.01 parts by mass were added as catalysts to the resulting dispersion to obtain an undercoat layer coating solution.
This undercoat layer coating solution was applied to the endless belt-like substrate surface by a dip coating method, followed by drying and curing at 160 ° C. for 100 minutes to obtain an undercoat layer having a thickness of 2 μm.

[Formation of charge generation layer]
Next, at a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum using a Cukα ray as a charge generation material, at least 7.5 °, 9.9 °, 12.5 °, 16.3. 15 parts of hydroxygallium phthalocyanine from which clear diffraction peaks are obtained at positions of 18.6 °, 28.6 °, 28.1 °, butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a binder resin 10 A mixture consisting of 300 parts of n-butyl alcohol was dispersed in a sand mill for 4 hours.
The obtained dispersion was applied as a charge generation layer coating solution by dip coating on the surface of the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.

[Formation of charge transport layer]
Next, 2 parts by mass of di (3,4-dimethylphenyl) (4-phenylphenyl) amine and N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl ] 4 parts of 4,4'-diamine and 6 parts by weight of bisphenol Z polycarbonate (molecular weight 40,000), 1 part by weight of nanompur (Frontier Carbon Co., Ltd., C60 fullerene), 80 parts by weight of tetrahydrofuran, 2, 6 -0.2 part by mass of di-t-butyl-4-methylphenol was added and dissolved. The obtained liquid was applied as a charge transport layer coating solution by dip coating on the surface of the charge generation layer and dried at 120 ° C. for 40 minutes to form a charge transport layer having a thickness of 25 μm.
As a result, an intermediate transfer member of the present invention having the layer structure shown in FIG. 5A was obtained.

The surface microhardness of the intermediate transfer belt A1 was measured by the above-described measurement method (measurement conditions were the same as above) using an ultra-micro hardness meter DUH-201S, and found to be 21 degrees.
Further, when the intermediate transfer belt A1 is mounted in the image forming apparatus, the volume resistivity of the outer peripheral surface of the intermediate transfer belt A1 before and after irradiation is measured under the same conditions as the red LED used as the static elimination lamp 91. As a result, the volume resistivity when not irradiated was 10 ¹⁴ Ωcm or more, and immediately after irradiation was 1 × 10 ^9.5 Ωcm. As described above, the volume resistivity was measured using a circular electrode (High Probe IP HR probe manufactured by Dia Instruments Co., Ltd.) in a 22 ° C./55% RH environment. A voltage of 100 (V) was applied between the cylindrical electrode portion C ′ and the second voltage application electrode B ′ in the one voltage application electrode A ′, and the current value after 10 seconds was obtained.

<Preparation of Intermediate Transfer Belt A2>
[Formation of belt-shaped substrate]
In the same manner as the intermediate transfer belt A1, an endless belt-like base material having an elastic layer was prepared.

[Formation of elastic layer]
-Preparation of elastic layer forming coating solution (A)-
100 parts by mass of Coronate 4028 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as isocyanate, 93 parts by mass of Nipponran 4599 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as polyol, and carbon black (trade name: Printex 140U (pH 4) as conductive agent .5): 22 parts by mass of Degussa Japan Co., Ltd.) were mixed to prepare an elastic layer forming coating solution (A).

-Formation of elastic layer-
Subsequently, the coating film is formed by applying the elastic layer forming coating solution (A) on the same endless belt-like base material used for the intermediate transfer belt A1 coated so as to cover the outer periphery of the cylindrical mold. Then, this coating film was cured by heating at a temperature of 80 ° C. for 120 minutes to form an elastic layer having a thickness of 0.5 mm. The elastic layer obtained had a JIS-A hardness of 45 °. Further, the volume resistivity of this two-layer belt in which the base material and the elastic layer were laminated was 3 × 10 ¹⁰ Ωcm.

  Subsequently, an undercoat layer, a charge generation layer, and a charge transport layer were sequentially formed on the elastic layer surface in the same manner as the intermediate transfer belt A1. As a result, an intermediate transfer belt A2 of the intermediate transfer member of the present invention having the layer structure shown in FIG. 5C was obtained.

The surface microhardness of the intermediate transfer belt A2 and the volumetric low efficiency before and after light irradiation by the red LED were measured in the same manner as the intermediate transfer belt A1. The surface microhardness was 1 degree, and the volume resistivity when not irradiated was 10%. ¹⁴ Ωcm or more and 3 × 10 ¹⁰ Ωcm immediately after irradiation. As described above, the volume resistivity was measured using a circular electrode (High Probe IP HR probe manufactured by Dia Instruments Co., Ltd.) in a 22 ° C./55% RH environment. A voltage of 100 (V) was applied between the cylindrical electrode portion C ′ and the second voltage application electrode B ′ in the one voltage application electrode A ′, and the current value after 10 seconds was obtained.

<Preparation of Intermediate Transfer Belt A3>
An endless belt-like substrate having a surface protective layer was prepared in the same manner as the intermediate transfer belt A1.

[Formation of undercoat layer]
A mixture (γ-amino) of 170 parts by mass of n-butyl alcohol, 30 parts by mass of an organic zirconium compound (acetylacetone zirconium butyrate) in which 4 parts by mass of polyvinyl butyral resin (Surek BM-S manufactured by Sekisui Chemical Co., Ltd.) was dissolved 3 parts by mass of (propyltrimethoxysilane) was further mixed and stirred to obtain a coating solution for an undercoat layer. An undercoat layer was applied to the surface of the endless belt-like substrate using a dip coating apparatus, and a curing treatment at 150 ° C. for 1 hour was performed to form an undercoat layer having a thickness of 1.0 μm.

[Formation of charge generation layer]
Next, at least at 7.5 °, 9.9 °, 12.5 °, 16.3 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα rays as the charge generation material. , 18.6 [deg.], 25.1 [deg.], 28.1 [deg.], 15 parts of hydroxygallium phthalocyanine from which clear diffraction peaks are obtained, and 10 parts of butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a binder resin A mixture of 300 parts of n-butyl alcohol was dispersed for 4 hours in a sand mill. The obtained dispersion was used as a coating solution for the charge generation layer, which was dip-coated on the surface of the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.

[Formation of charge transport layer]
Next, 2 parts by mass of di- (3,4-dimethylphenyl) (4-phenylphenyl) amine and N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′- Biphenyl] -4,4′-diamine (2 parts by mass), bisphenol Z polycarbonate (molecular weight 40,000) (6 parts by mass) and Nanommix (frontier carbon, fullerene mixture) (1 part by mass) tetrahydrofuran 80 parts by mass, 2,6 -0.2 part by mass of di-t-butyl-4-methylphenol was added and dissolved. The obtained liquid was applied as a charge transport layer coating solution by dip coating on the surface of the charge generation layer and dried at 120 ° C. for 40 minutes to form a charge transport layer having a thickness of 25 μm.

[Formation of surface protective layer]
And 2 mass parts of the compounds shown below, 2 mass parts of methyltrimethoxysilane, 1 mass part of tetramethoxysilane, 0.3 mass part of colloidal silica, 5 mass parts of isopropyl alcohol, 3 mass parts of tetrahydrofuran, 3 masses of distilled water After the ion exchange resin (0.5 parts) was added and hydrolyzed at room temperature for 24 hours, the ion exchange resin was separated by filtration, 0.1 parts of aluminum trisacetylacetonate, 3,5-t- 0.4 parts of butyl-4-hydroxytoluene (BHT) was added to prepare a coating solution. This coating solution was dip-coated on the surface of the charge transport layer and dried at 150 ° C. for 1 hour to obtain a surface protective layer having a thickness of 3 μm.

これにより、図５（Ｂ）に記載の層構成を有する本発明の中間転写体を得た。

As a result, an intermediate transfer member of the present invention having the layer structure shown in FIG. 5B was obtained.

The surface microhardness of the intermediate transfer member in the intermediate transfer belt A3 was measured in the same manner as in the intermediate transfer belt A1, and found to be 30 degrees. Further, the volume resistivity of the intermediate transfer belt A3 when not irradiated with the intermediate transfer member is 2 × 10 ¹⁴ Ωcm, the volume resistivity immediately after irradiation is 1 × 10 ¹⁰ Ωcm, and the surface resistivity is 1 × 10 ¹⁴ Ω. / □.

<Preparation of intermediate transfer belt A4>
In the intermediate transfer belt A1, an intermediate transfer member of the present invention having the layer structure shown in FIG. 5C was obtained in the same manner except that 5 mass of a fluorine-based resin was further added to the charge transport layer.
Here, the surface microhardness of the intermediate transfer member in the intermediate transfer belt A4 was measured and found to be 18 degrees. Further, the volume resistivity of the intermediate transfer member in the intermediate transfer belt A4 was 3 × 10 ¹⁴ Ωcm, and the surface resistivity was 3 × 10 ¹⁴ Ω / □.

<Preparation of intermediate transfer belt A5>
In the intermediate transfer belt A3, the intermediate transfer member of the present invention having the layer structure shown in FIG. 5B is obtained in the same manner except that 1 part by mass of a fluorine-based resin is further added to the formation of the surface protective layer. It was.
Here, the surface microhardness of the intermediate transfer member in the intermediate transfer belt A5 was measured and found to be 20 degrees. Further, the volume resistivity of the intermediate transfer belt A5 when the intermediate transfer member is not irradiated is 2 × 10 ¹⁴ Ωcm, the volume resistivity immediately after irradiation is 2 × 10 ¹⁰ Ωcm, and the surface resistivity is 2 × 10 ¹⁴ Ω / □. Met.

<Preparation of Intermediate Transfer Belt B1>
(Preparation of polyamic acid solution (B))
N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-diaminodiphenyl ether (DDE) (manufactured by Ube Industries) To Euvarnish S (solid content: 18% by mass), 100 parts by mass of the solid content of the raw material capable of forming the polyimide resin in this solution, dry oxidized carbon black (SPECIAL BLACK4 (manufactured by Degussa, pH 3.0, volatile content: 14.0%)) is added to 25 parts by mass, using a collision type disperser (GeanusPY made by Genus), pressure is 200 MPa, and the minimum area is 1.4 mm ² and divided into two. It was made to collide afterwards, and the passage which divided into 2 again was passed 5 times, it mixed, and the polyamic-acid solution (A) containing carbon black for base materials was obtained.

(Belt formation)
The polyamic acid solution (B) containing carbon black is applied to the inner surface of the cylindrical mold so that the thickness of the coating film becomes 0.5 mm via a dispenser, and the mold is rotated at 1500 rpm for 15 minutes to obtain a uniform thickness. After forming the coating film having a temperature of 60 ° C from the outside of the mold for 30 minutes while rotating the mold at 250 rpm, the coating film was heated to 150 ° C for 60 minutes and cooled to room temperature. Formed.
Thereafter, the film formed on the inner surface of the mold is peeled off, and this film is coated so as to cover the outer periphery of the metal core, and the temperature is increased to 400 ° C. at a rate of 2 ° C./min. For 30 minutes to remove the solvent and dehydrated ring-closing water remaining in the film and complete the imide conversion reaction. Thereafter, after cooling the metal core to room temperature, the polyimide film formed on the surface of the metal core was peeled off to obtain an endless belt-like base material (intermediate transfer belt B1) having a thickness of 0.08 mm. .
The obtained base material (intermediate transfer belt B1) had a Young's modulus of 3800 MPa, a volume resistivity of 1 × 10 ^9.2 Ωcm and a surface resistivity of 5 × 10 ¹¹ Ω / □ both when unirradiated and irradiated. .

  The surface microhardness of the intermediate transfer belt B1 and the volume resistivity before and after light irradiation by the red LED were measured in the same manner as in the intermediate transfer belt A1, and the surface microhardness was 28 degrees. There was no change in the volume resistivity immediately after, and no photoconductivity was exhibited.

<Preparation of intermediate transfer belt B2>
In the formation of the charge transport layer of the intermediate transfer belt A1, the same method as in Example 1, except that it was prepared without adding 1 part by mass of nanom purple (manufactured by Frontier Carbon Co., Ltd., C60 fullerene). An intermediate transfer belt B2 having the layer configuration shown in FIG. The film thickness of the charge transport layer was 25 μm.
Here, the surface microhardness of the intermediate transfer member in Comparative Example 1 was measured using an ultra-micro hardness meter DUH-201S and found to be 21 degrees. Further, the volume resistivity of the intermediate transfer member in Example 1 was 1 × 10 ¹⁴ Ωcm both when unirradiated and irradiated, and the surface resistivity was 1 × 10 ¹⁴ Ω / □.

<Preparation of Intermediate Transfer Belt B3>
In the production of the intermediate transfer belt A3, the same method as in Example 2 was applied except that 1 part by mass of Nanomumix (manufactured by Frontier Carbon Co., Ltd., fullerene mixture) was added without being added in Comparative Example 2. The intermediate transfer member of the present invention having the layer structure shown in FIG. 1B was obtained.
Here, the surface microhardness of the intermediate transfer member in Comparative Example 3 was measured using an ultra-micro hardness meter DUH-201S and found to be 21 degrees. Further, the volume resistivity of the intermediate transfer member in Example 1 was 2 × 10 ¹⁴ Ωcm, and the surface resistivity was 1 × 10 ¹⁴ Ω / □.

<Preparation of intermediate transfer belt B4>
An intermediate transfer member was prepared in the same manner as the intermediate transfer belt A1 except that the charge generation layer and the undercoat layer were not provided.
Here, the surface microhardness of the intermediate transfer member in Comparative Example 3 was 28 degrees as measured using an ultra-micro hardness meter DUH-201S. Further, the volume resistivity of the intermediate transfer member in Example 1 was 2 × 10 ¹⁰ Ωcm, and the surface resistivity was 8 × 10 ¹¹ Ω / □.

<Configuration of Cleaning Device A1>
The cleaning device A1 is a cleaning device having the configuration shown in FIG. 4B, which includes a brush member and a cleaning blade of the type used in the first aspect of the present invention. Details will be described below.
-Conductive brush-
・ Material: Conductive nylon (Thickness: 2 denier (about 17μm))
・ Electric resistance: 1 × 10 ⁵ Ω
-Hair length: 4mm
・ Density: 7.8 × 10 ³ / cm ² (50,000 / inch ² )
-Biting into the intermediate transfer member: approx. 1.5 mm
・ Peripheral speed: 60mm / s
・ Rotation direction: Forward rotation with respect to the rotation direction of the intermediate transfer member)
・ Brush application bias: + 200V

-Cleaning blade-
A polyurethane cleaning blade having a thickness of 2 mm and a length of 8 mm was used. Various characteristics of this cleaning blade are as follows.
-Rebound resilience coefficient at 10 ° C = 18%
・ Rebound resilience at 40 ℃ = 60%
・ 300% modulus = 2800N / cm ²
・ Tear strength = 730 N / cm
・ 100% permanent elongation (JIS K6262) = 3.8%

Further, the mounting conditions of the cleaning blade are as follows.
-Contact angle = 25 degrees-Linear pressure = 0.5 N / cm

<Configuration of Cleaning Device A2>
The cleaning device A2 is a cleaning device having the structure shown in FIG. 2 provided with two cleaning units including brush members of the type used in the first aspect of the present invention. Details will be described below.

[First cleaning unit (upstream in the intermediate transfer belt rotation direction)]
-Conductive brush-
・ Material: Conductive nylon (Thickness: 2 denier (about 17μm))
・ Electric resistance: 1 × 10 ⁵ Ω
-Hair length: 4mm
・ Density: 7.8 × 10 ³ / cm ² (50,000 / inch ² )
-Biting into the intermediate transfer member: approx. 1.5 mm
・ Peripheral speed: 60mm / s
・ Rotation direction: Forward rotation with respect to the rotation direction of the intermediate transfer member)
・ Brush application bias: + 200V

-Conductive roll-
・ Material: Metal core covered with 0.06 mm thick polyimide resin ・ Electric resistance: 5 × 10 ⁸ Ω
・ Abrasion amount: 2mg
-Biting into the brush: 1.5mm
・ Peripheral speed: 70mm / s
-Applied bias: + 600V

-Scraper-
・ Material: SUS304
・ Thickness: 80μm
-Biting amount: 1.3 mm
・ Free length: 8.0mm

[Second cleaning unit (on the downstream side in the rotation direction of the intermediate transfer belt)]
-Conductive brush-
・ Material: Conductive nylon (Thickness: 2 denier (about 17μm))
・ Electric resistance: 1 × 10 ⁵ Ω
-Hair length: 4mm
・ Density: 7.8 × 10 ³ / cm ² (50,000 / inch ² )
-Biting into the intermediate transfer member: approx. 1.5 mm
・ Peripheral speed: 60mm / s
・ Rotation direction: Forward rotation with respect to the rotation direction of the intermediate transfer member ・ Brush applied bias: −400 V

-Conductive roll-
・ Material: Metal core covered with 0.07mm thick polyimide resin ・ Electric resistance: 5 × 10 ⁸ Ω
・ Abrasion amount: 2mg
-Biting into the brush: 1.5mm
・ Peripheral speed: 70mm / s
-Applied bias: -800V

-Scraper-
・ Material: SUS304
・ Thickness: 80μm
-Biting amount: 1.3 mm
・ Free length: 8.0mm

<Configuration of Cleaning Device B1>
The cleaning device B1 is a cleaning device having only a cleaning blade of the type used in the second aspect of the present invention. Details will be described below.

-Cleaning blade-
A polyurethane cleaning blade having a thickness of 2 mm and a length of 8 mm was used. Various characteristics of this cleaning blade are as follows.
-Rebound resilience coefficient at 10 ° C = 18%
・ Rebound resilience at 40 ℃ = 60%
・ 300% modulus = 2800N / cm ²
・ Tear strength = 730 N / cm
・ 100% permanent elongation (JIS K6262) = 3.8%
Further, the mounting conditions of the cleaning blade are as follows.
-Contact angle = 25 degrees-Linear pressure = 0.5 N / cm

<Configuration of Cleaning Device B2>
The cleaning device B2 is a cleaning device having only a cleaning blade of the type used in the second aspect of the present invention. Details will be described below.
-Preparation of cleaning blade-
Urethane rubber: 1,9-nonanediol / 2-methyl-1,8-octanediol (molar ratio 65/35), adipic acid, and 2000 molecular weight polyester polyadipic acid are reacted to yield a 2000 molecular weight polyester polyol. Got. The ester concentration in this polyester polyol is 6.8 mmol / g.
Subsequently, the polyester polyol was reacted with a mixture of 1,3-propanediol and trimethylolethane as a chain extender to obtain a cleaning blade made of urethane rubber having a plate thickness of 2 mm and a length of 8 mm.

Various characteristics of the cleaning blade are as follows.
-Rebound resilience at 10 ° C = 22%
・ Rebound resilience at 40 ℃ = 60%
・ 300% modulus = 2300N / cm ²
・ Tear strength = 840 N / cm
・ 100% permanent elongation (JIS K6262) = 2.5%

Further, the mounting conditions of the cleaning blade are as follows.
-Contact angle = 28 degrees-Linear pressure = 0.3 N / cm

<Configuration of Cleaning Device C1>
The cleaning device C1 is a cleaning device having the configuration shown in FIG. 4A, which includes a cleaning blade of the type used in the second aspect of the present invention, a cleaning brush, and a solid lubricant supply means. Details will be described below.

-Cleaning brush-
・ Material: Acrylic fiber with carbon added (thickness: 2 denier (about 17μm))
・ Electric resistance: 5 × 10 ⁵ Ω
-Hair length: 4mm
Density: 8.5 × 10 ³ / cm ² (55,000 / inch ² )
-Biting into the intermediate transfer member: approx. 1.5 mm
・ Peripheral speed: 220 mm / s
・ Rotation direction: Forward rotation with respect to the rotation direction of the intermediate transfer member

-Solid lubricant (supplying means)-
The solidified zinc stearate was used, and the contact state (the biting depth, the contact area, etc.) with the cleaning brush was adjusted so that the consumption per rotation of the intermediate transfer member was about 0.1 μg.

-Cleaning blade-
A polyurethane cleaning blade having a thickness of 2 mm and a length of 8 mm was used. Various characteristics of this cleaning blade are as follows.
-Rebound resilience coefficient at 10 ° C = 18%
・ Rebound resilience at 40 ℃ = 60%
・ 300% modulus = 2800N / cm ²
・ Tear strength of angle type = 730 N / cm
・ 100% permanent elongation (JIS K6262) = 3.8%

Further, the mounting conditions of the cleaning blade are as follows.
-Contact angle = 25 degrees-Linear pressure = 0.5 N / cm

(Evaluation)
The toner, intermediate transfer belt, and cleaning device listed above were combined and evaluated by the following method.

(Evaluation of transfer image quality)
The transfer image quality (hollow character, blur), cleaning property evaluation method and evaluation criteria in Tables 1 and 2 are as follows.

-Image quality (Holo-Character)-
The occurrence of holocharacters in the initial image was evaluated according to the following criteria.
A: There is no problem in image quality.
○: There are few occurrences of holo characters and there is no problem with image quality.
Δ: There are a few occurrences of holo characters, but there are few problems with image quality.
×: There is a generation of holo characters, and there is a problem with image quality.

-Image quality (blur)-
The occurrence of blur in the initial image was evaluated according to the following criteria.
A: There is no occurrence of blur.
○: Blur is slight and there is no problem in image quality.
Δ: There is little blurring, but there are few problems with image quality.
X: Blur occurs and there is a problem in image quality.

−Cleanability−
The cleaning property after printing 10,000 sheets continuously was judged according to the following criteria.
○: No cleaning failure △: Slight cleaning failure occurs, but there are few image quality problems ×: There is a cleaning property failure and image quality problem

  The results based on the evaluation method are shown in Tables 1 and 2 below.

(Evaluation results)
In Examples 1 to 16, uniform images without density unevenness and blur (toner scattering) were obtained in the first print sample. Here, immediately after the secondary transfer, the surface potential of the intermediate transfer belt 22 had surface potential unevenness that seems to correspond to an image pattern of about −300 V to −400 V. When the charge removal by the charge removal conductive member 90 was performed, the surface potential of the intermediate transfer belt 22 became substantially uniform between -10V and -30V.
Subsequently, even in the second print sample, a uniform image free from density unevenness and blur (toner scattering) was obtained. Similarly, although 10,000 sheets were output continuously, a good image equivalent to offset printing without density unevenness and blur (toner scattering) was obtained.

  Comparative Examples 1 to 5 do not contain fullerene in the intermediate transfer belt. Here, an image with little density unevenness was obtained in the first print sample. However, density unevenness occurred in the second and subsequent print samples, and continuous image quality evaluation could not be performed.

  The intermediate transfer belt used in Comparative Example 6 does not have a photoconductive layer because the charge generation layer is not provided. When an image is formed using such an intermediate transfer belt, image quality defects such as toner scattering occur, and the image quality is at a problematic level.

  As shown in Table 1 and Table 2, the intermediate transfer member surface layer is a photoconductive layer containing fullerene, and the outer peripheral surface is a dielectric in a state where light is not irradiated and has a high volume resistivity, and An intermediate transfer member having a function of exhibiting conductivity when irradiated with light, and a light discharging means for discharging the outer peripheral surface of the intermediate transfer member after passing through the secondary transfer portion by irradiating with light. In the case of an image forming apparatus, particularly when the image forming apparatus further includes a cleaning unit that cleans the outer peripheral surface of the intermediate transfer member after being neutralized by light irradiation of the light neutralizing unit, Even when a toner having a reduced diameter and a substantially spherical shape was used, the toner remaining on the surface of the intermediate transfer member after the secondary transfer was excellent in cleaning properties, and a high-quality image could be stably formed.

1 is a schematic diagram illustrating a configuration example of an image forming apparatus of the present invention. FIG. 2 is a schematic diagram illustrating a configuration example of a cleaning device that can be suitably used in the image forming apparatus of the present invention. It is a schematic diagram showing another example of the image forming apparatus of the present invention. It is a schematic diagram which shows another example of a structure of the cleaning apparatus which can be used suitably for the image forming apparatus of this invention. FIG. 2 is a schematic cross-sectional view showing a configuration example of an intermediate transfer member used in the present invention, (A) is a schematic cross-sectional view showing a configuration of an intermediate transfer member 100a of the present invention, and (B) is an intermediate transfer member of the present invention. FIG. 10C is a schematic cross-sectional view showing the configuration of the intermediate transfer member 100c of the present invention, and FIG. 10D is a schematic cross-sectional view showing the configuration of the intermediate transfer member 100d of the present invention. It is. It is the schematic plan view (A) and schematic sectional drawing (B) which show an example of a circular electrode. It is a schematic diagram which shows the measurement principle of the surface micro hardness of a surface layer. It is explanatory drawing of the technique of Unexamined-Japanese-Patent No. 7-146616 which is patent document 11. FIG. It is explanatory drawing of the technique of Unexamined-Japanese-Patent No. 7-146616 which is patent document 11. FIG. It is explanatory drawing of the technique of Unexamined-Japanese-Patent No. 5-257398 which is the patent document 12. FIG. It is explanatory drawing of the problem which arises when transferring the developed image of the 2nd color by the technique of Unexamined-Japanese-Patent No. 5-257398 which is patent document 12. FIG. It is explanatory drawing of the technique which transfers by light irradiation using the intermediate transfer body which resistance value falls by light irradiation of Unexamined-Japanese-Patent No. 6-282181 which is patent document 13. FIG. It is explanatory drawing of the technique which transfers by application of pressurization using the intermediate transfer body which resistance value falls by the pressurization of Unexamined-Japanese-Patent No. 6-282181 which is patent document 13. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 15 Cleaning apparatus 11a, 11b Conductive brush 12a, 12b Conductive roll 13a, 13b Scraper 14, 19 Housing | casing 16 Cleaning blade 17 Cleaning brush 18 Solid lubricant supply means 21 Photosensitive drum (image carrier)
22 Intermediate transfer belt (intermediate transfer member)
23 Bias roller (secondary transfer part)
24 Paper tray 25 Black developing device 26 Yellow developing device 27 Magenta developing device 28 Cyan developing device 33 Peeling claw 41, 43, 44 Belt roller 42 Backup roller 45 Conductive roll (primary transfer portion)
46 Electrode roller 50 Static elimination roll 51 Cleaning blade 61 Recording paper (transfer material)
62 Pickup roller 63 Feed roller 71 Toner cartridge 72 Fixing roll 73 Backup roll 74 Tension roll 75 Secondary transfer roll 76 Paper path 77 Paper tray 78 Laser generator 79 Photoconductor 80 Primary transfer roll 81 Drive roll 83 Charging roll 84 Photoconductor Cleaner 85 Developer 86 Intermediate transfer belt (intermediate transfer member)
90 Electrostatic member 91 for static elimination Electrostatic discharge lamps 100a, 100b, 100c, 100d Intermediate transfer member 110 Base material 113 Adhesive layer 115 Elastic layer 120 Surface layer 122 Undercoat layer 124 Charge generation layer 126 Charge transport layer 128 Surface protective layer 150 Needle-shaped indenter 152 Surface layer T Toner Q3 Primary transfer area Q4 Secondary transfer area Q5 Static elimination area

Claims (8)

An intermediate transfer body having at least a base material and a surface layer provided on the base material,
An intermediate transfer member, wherein the surface layer is a photoconductive layer containing fullerene. The photoconductive layer has at least a charge generation layer and a charge transport layer;
The charge generation layer is provided between the base material and the charge transport layer,
The intermediate transfer member according to claim 1, wherein the charge transport layer contains fullerene.   The intermediate transfer member according to claim 1 or 2, wherein a layer farthest from the base material among the surface layers contains a fluororesin. An image carrier on which a toner image is formed; and
An outer peripheral surface abuts on the surface of the image carrier, a primary transfer portion that transfers the toner image from the surface of the image carrier to the outer peripheral surface, and the toner image transferred to the outer peripheral surface to a transfer material. An intermediate transfer member composed of a rotating member having a secondary transfer portion to be transferred;
4. The intermediate transfer according to claim 1, further comprising: a light neutralizing unit that irradiates light on an outer peripheral surface of the intermediate transfer body after passing through the secondary transfer portion. 5. An image forming apparatus characterized by being a body. And a cleaning means for cleaning the outer peripheral surface of the intermediate transfer member after the charge removal,
The cleaning unit includes one or more cleaning units including a brush member that contacts the outer peripheral surface of the intermediate transfer member, and a voltage is applied to the brush member when the outer peripheral surface of the intermediate transfer member is cleaned. The image forming apparatus according to claim 4. And a cleaning means for cleaning the outer peripheral surface of the intermediate transfer member after the charge removal,
The image forming apparatus according to claim 4, wherein the cleaning unit includes a cleaning blade that contacts an outer peripheral surface of the intermediate transfer member. The cleaning means includes a cleaning brush that is in contact with the outer peripheral surface of the intermediate transfer member and is rotatable, and a lubricant application unit that applies a solid lubricant to the outer peripheral surface of the intermediate transfer member via the cleaning brush,
The image forming apparatus according to claim 6, wherein the cleaning brush is disposed upstream of the cleaning blade in the rotation direction of the intermediate transfer member. 8. The image forming apparatus according to claim 4, wherein a shape factor SF defined by the following formula (1) of the toner is in a range of 100 to 140. 10.
Formula (1); SF = [(maximum length of toner particles) ² × π × 100] / [projection area of toner particles × 4]

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